* Track trending tags

- Half-life of 1 day
- Historical usage in daily buckets (last 7 days stored)
- GET /api/v1/trends

Fix #271

* Add trends to web UI

* Don't render compose form on search route, adjust search results header

* Disqualify tag from trends if it's in disallowed hashtags setting

* Count distinct accounts using tag, ignore silenced accounts

Original patch by @j-a4

* Ensure push subscription is immediately removed when application is revoked

* When token is revoked from app, unsubscribe too

> Good lord what is happening in there

Previously the contents of the Web Push API payloads closely resembled the structure of JavaScript's [Notification](https://developer.mozilla.org/en-US/docs/Web/API/Notification). But now that the API is open to non-browser apps, and given that there is no required coupling between contents of the payload and a Notification object, here is how I changed the payload:

```json
{ 
  "access_token": "...",
  "preferred_locale": "en",
  "notification_id": "12345",
  "notification_type": "follow",
  "title": "So and so followed you",
  "body": "This is my bio",
  "icon": "https://example.com/avatar.png"
}
```

The title, body and icon attributes are included as a fallback so you can construct a minimal notification if you cannot perform a network request to the API to get more data.

* Add preference to hide following/followers lists

- Public pages
- ActivityPub collections (does not return pages but does give total)
- REST API (unless it's your own) (does not federate)

Fix #6901

* Add preference

* Add delegation

* Fix issue

* Fix issue

Fix #7462

- POST /api/v1/push/subscription
- PUT /api/v1/push/subscription
- DELETE /api/v1/push/subscription
- New OAuth scope: "push" (required for the above methods)

* Store actor type in database

* Add bot nameplate to web UI, add setting to preferences, API, AP
Fix #7365

* Fix code style issues

Follow-up to #6124

Fix #7303

* Store home feeds for 7 days instead of 14

Reduces workload for status fan-out to active followers

* Fix test for user model

Same URI passed between follow request and follow, since they are
the same thing in ActivityPub. Local URIs are generated during
creation using UUIDs and are passed to serializers.

* Revert "Fixes/do not override timestamps (#7331)"

This reverts commit 581a5c9d29.

* Document Snowflake ID corner-case a bit more

Snowflake IDs are used for two purposes: making object identifiers harder to
guess and ensuring they are in chronological order. For this reason, they
are based on the `created_at` attribute of the object.

Unfortunately, inserting items with older snowflakes IDs will break the
assumption of consumers of the paging APIs that new items will always have
a greater identifier than the last seen one.

* Add `override_timestamps` virtual attribute to not correlate snowflake ID with created_at

* Keep notification when muting_notifications is true

* Retrun mute object

* Fix test

Add raw bio fields to the source attribute on GET /api/v1/accounts/verify_credentials

One RSA keypair for all fabricated test accounts is enough

* Add entity cache

Use a caching layer for mentions and custom emojis that are
dynamically extracted from text.

Reduce duplicate text extractions

* Fix code style issue

The goal here isn't to prevent these hashtags from existing, but just to strongly curtail their usage; The hashtags may still exist in the database via federated status, or from being created prior to this feature.

* Update annotate to version 2.7.3

* Update aws-sdk-s3 to version 1.9.2

* Update browser to version 2.5.3

* Update capistrano to version 3.10.2

* Update domain_name to version 0.5.20180417

* Update http to version 3.2.0

* Update lograge to version 0.10.0

* Update oj to version 3.5.1

* Update parallel_tests to version 2.21.3

* Update puma to version 3.11.4

* Update rubocop to version 0.55.0

* Update scss_lint to version 0.57.0

* Update simplecov to version 0.16.1

* Update tty-command to version 0.8.0

* Update tty-prompt to version 0.16.0

* Update pkg-config to version 1.3.0

* Update fog-local to version 0.5.0

* Update fog-openstack to version 0.1.25

* Update devise-two-factor to version 3.0.3

* bundle update

Fix #7198 by allowing records with optional attachments to save

* Force convert to JPG for preview card thumbnails to avoid animations

Fix #7093

* Conditionally convert to JPG only if original is GIF
Coalesce and strip on all formats to ensure no animated APNGs

* Added a timeline for Direct statuses
* Lists all Direct statuses you've sent and received
* Displayed in Getting Started
* Streaming server support for direct TL

* Changes to match other timelines in 2.0

* Add bio fields

- Fix #3211
- Fix #232
- Fix #121

* Display bio fields in web UI

* Fix output of links and missing fields

* Federate bio fields over ActivityPub as PropertyValue

* Improve how the fields are stored, add to Edit profile form

* Add rel=me to links in fields

Fix #121

This also limits the statuses returned by API, but pagination is not
implemented in Web API yet. I still expect it brings user experience
better than making a user wait to fetch all ancestor statuses and flooding
the column with them.

* Further improvements to Reports UI

- Clean up notes display
- Clean up add new note form
- Simplify controller
- Allow reopening a report with a note
- Show created at date for reports
- Fix report details table formatting

* Show history of report using Admin::ActionLog beneath the report

* Fix incorrect log message when reopening a report

* Implement fetching of all ActionLog items that could be related to the report

* Ensure adding a report_note updates the report's updated_at

* Limit Report History to actions that happened between the report being created and the report being resolved

* Fix linting issues

* Improve report history builder

Thanks @gargron for the improvements

* Admin: Show unconfirmed email address on account page

* Admin: Allow staff to change user email addresses

* ActionLog: On change_email, log current email address and new unconfirmed email address

- Explicitly specify video codec.
  When ffmpeg isn't compiled with libx264 but openh264, mpeg4 is selected as video codec.
- Swap avarage bitrate and max bitrate.

ancestor_statuses and descendant_statuses used to include the root status
itself, but the behavior is confusing because the root status is not
an ancestor nor descendant.

* Implement Assignment of Reports (#6967)

* Change translation of admin.report.comment.label to "Report Comment" for clarity

As we'll soon add the ability for reports to have comments on them, this clarification makes sense.

* Implement notes for Reports

This enables moderators to leave comments about a report whilst they work on it

* Fix display of report moderation notes

* Allow reports to be reopened / marked as unresolved

* Redirect to reports listing upon resolution of report

* Implement "resolve with note" functionality

* Add inverse relationship for report notes

* Remove additional database querying when loading report notes

* Fix tests for reports

* Fix localisations for report notes / reports

Federate custom emojis with accounts

Comparison was downcasing only one side, therefore if previously
existing account had a non-lowercase spelling, it would be ignored
when checking for duplicates.

New rake task `mastodon:maintenance:find_duplicate_usernames` will
help find constraint violations that might have occured from the
presence of this bug.

Bump version to 2.3.3

to_s method of HTTP::Response keeps blocking while it receives the whole
content, no matter how it is big. This means it may waste time to receive
unacceptably large files. It may also consume memory and disk in the
process. This solves the inefficency by checking response length while
receiving.

HTTP connections must be explicitly closed in many cases, and letting
perform method close connections makes its callers less redundant and
prevent them from forgetting to close connections.

Usernames with dots in them do not work with routes, because the dot usually separates the desired page format (e.g. json). I don't want to mess with changing route constraints for this patch release.

* Permit dots in usernames with conditions

- Dot cannot be the start or end of username
- a.lice and al.ice are considered the same during sign-up

* Fix regex mixin flags

* update to new version of devise_pam_authenticatable2

* fix behaviour if suffix is nil, fix environment loading, fix user email creation

* code cleanup/fix linter warning

This will prevent, for example, `rake mastodon:redownload_avatars` from crashing when an instance is no longer responding to connection attempts, instead silently continuing as expected.

* Rescue when there's no extension in the remotable
Sometimes the remotable is pointing to a directory with no file
extension. Maybe it should not be expecting to identify based on
extensions to begin with, but since it's the case, it should be ready
for it.

* Fix codeclimate issue

* Check if filename is nil instead of rescueing exception
Suggestion made in the PR

* Avoid concatenation issue if filename is nil
If filename is nil, extname was undefined

* Invert condition
Address PR comments