Fixes #16435

Fixes #12920

warning: only hide for web, api may also need to change

* Add featured tag support to rss feed on public account page

* fix codeing style

It resolves #11338

Fix #11453

* Remove Salmon and PubSubHubbub endpoints

* Add error when trying to follow OStatus accounts

* Fix new accounts not being created in ResolveAccountService

* Revert "Fix filtering of favourited_by, reblogged_by, followers and following (#10447)"

This reverts commit 120544067f.

* Revert "Hide blocking accounts from blocked users (#10442)"

This reverts commit 62bafa20a1.

* Improve blocked view of profiles

- Change "You are blocked" to "Profile unavailable"
- Hide following/followers in API when blocked
- Disable follow button and show "Profile unavailable" on public profile as well

* Add hashtag filter to profiles

GET /@:username/tagged/:hashtag
GET /api/v1/accounts/:id/statuses?tagged=:hashtag

* Display featured hashtags on public profile

* Use separate model for featured tags

* Update featured hashtag counters on-write

* Limit featured tags to 10

Hello,
The ATOM feed contains the hub declaration for WebSub, but the RSS
version does not.
RSS/ATOM readers will typically pick whichever version comes first, and
will thus not see the WebSub feature.
I therefore suggest putting the ATOM version first, as it is more
feature-rich than its RSS counterpart is.

Clients not compatible with ATOM would not pick it anyway due to the
different type attribute.

A more complicated alternative would be to declare the WebSub feature in
the RSS version as well, using something like the following code, and
ensuring that clients subscribed to the RSS version would receive PuSH
updates just like those subscribed to the ATOM version.

````xml
<rss version="2.0" xmlns:webfeeds="http://webfeeds.org/rss/1.0"
xmlns:atom="http://www.w3.org/2005/Atom">
<channel>
<atom:link rel="self" type="application/rss+xml"
href="https://diaspodon.fr/users/test.rss"/>
<atom:link rel="hub" href="https://diaspodon.fr/api/push"/>
</channel>
</rss>
```

Display summary of attachments in description, and mark up content
warning if present, e.g.:

    Attached: 3 images · Content warning: Dota 2

When text is not supposed to be hidden, it looks more like:

    Attached: 3 images

    Here is the text of the toot

With #6817, multilinguagility should be assured...

- Add missing meta description to profiles
- Add canonical rel link to landing page
- Remove linebreaks from title tags
- Add username to profile title
- Add toots/following/followers to profile description tags
- Add next/prev rel links to profiles
- Do not index follower/following variants of profiles

* Fix prev/next links on public profile page

* Don't make pagination urls if no available statuses

* Fix empty check method

* Put left chevron before prev page link

* Add scope for pagination "starting at" a given id

* Status pagination try 2:

s/prev/older and s/next/newer
"older" on left, "newer" on right
Use new scope for "newer" link
Extract magic 20 page size to constant
Remove max_id from feed pagination as it's not respected

* Reinstate max_id for accounts atom stream

* normalize

* Serialize moved accounts into REST and ActivityPub APIs

* Parse federated moved accounts from ActivityPub

* Add note about moved accounts to public profiles

* Add moved account message to web UI

* Fix code style issues

Fix #5597

- Return all images as og:image
- Return videos as og:image (preview) and og:video
- Return profile:username on profiles

* Pinned statuses

* yarn manage:translations

* Redesign public profiles

* Responsive design

* Change public profile status filtering defaults and add options

- No longer displays private/direct toots even if you are permitted access
- By default omits replies
- "With replies" option
- "Media only" option

* Redesign account grid cards

* Fix style issues

* Fix oddities with public profile CSS

* Remove trailing whitespace

* add og:url to stream_item view

* add og:url and text to about/show

* add og:url to profile, followers and follows pages

* Add meta tags for OGP to following & follow page

* simplify render helper

* Follow up #2133

* og:type is only accounts/show

* revert accounts/{following,followers}

* Simplify render in mailer views

* Simplify render in about/more view

* Simplify render in accounts follow views

* Simplify render in recovery code views

* Simplify render in stream entry embed

* Simplify render in stream entries status partial

* Simplify render in authorize follow new view

* Move site title helper to instance helper (name change only)

* Remove newline in <title> tag

* Add site_hostname helper method to wrap up local_domain value

* Use site_hostname helper in places that need local_domain value

* Use local vars in accounts/header partial

* Use local variable in 2fa recovery codes partial

* Add option to disable verify partial doubles

* Add show_landing_strip? helper method

* Use show_landing_strip? helper in accounts and stream entries views

* Fix naming in view specs

An attempt to open a brand new Mastodon instance configured
as SINGLE_USER_MODE=true will cause an exception.

Enable temporary registration if we have no users in the database

Fixes #1817

* Replace will_paginate with kaminari

* Use #page instead of #paginate in controllers

* Replace will_paginate.page_gap with pagination.truncate in i18n

* Customize kaminari views to match prior styles

* Set kaminari options to match prior behavior

* Replace will_paginate with paginate in views

* Add helper method to return Setting.site_title

* Use site_title helper in application layout

* Use site_title value for og:site_name

h-feed, h-card and h-entry