Fix #12554

* Remove Salmon and PubSubHubbub endpoints

* Add error when trying to follow OStatus accounts

* Fix new accounts not being created in ResolveAccountService

* Add test for not persisting status when attaching media to scheduled toot

* Prevent status used for validation from being persisted to the database

Fixes #9893

Thanks to tateisu for the help investigating this.

Fix #340

Fixes #9580

* Ensure replied-to is a status not a boost

* Consider case of not a reply

* Add test case for replying to boost

* Move reblog-reply resolution to model

* Remove unnecessary comment

* No need to re-require sidekiq plugins, they are required via Gemfile

* Add derailed_benchmarks tool, no need to require TTY gems in Gemfile

* Replace ruby-oembed with FetchOEmbedService

Reduce startup by 45382 allocated objects

* Remove preloaded JSON-LD in favour of caching HTTP responses

Reduce boot RAM by about 6 MiB

* Fix tests

* Fix test suite by stubbing out JSON-LD contexts

* Deliver ActivityPub Like

* Deliver ActivityPub Undo-Like

* Deliver ActivityPub Create/Announce activities

* Deliver ActivityPub creates from mentions

* Deliver ActivityPub Block/Undo-Block

* Deliver ActivityPub Accept/Reject-Follow

* Deliver ActivityPub Undo-Follow

* Deliver ActivityPub Follow

* Deliver ActivityPub Delete activities

Incidentally fix #889

* Adjust BatchedRemoveStatusService for ActivityPub

* Add tests for ActivityPub workers

* Add tests for FollowService

* Add tests for FavouriteService, UnfollowService and PostStatusService

* Add tests for ReblogService, BlockService, UnblockService, ProcessMentionsService

* Add tests for AuthorizeFollowService, RejectFollowService, RemoveStatusService

* Add tests for BatchedRemoveStatusService

* Deliver updates to a local account to ActivityPub followers

* Minor adjustments

duplicates. Web UI regenerates UUID for that header every time the compose
form is changed or successfully submitted

Also, fix Farsi i18n overwriting the English one

* Extract detect_language to separate class

* Use default locale, not just en

* Add spec to confirm that whatlanguage cant identify empty string

* Allow account locale to override default in language detector

* PostStatusService supplies an account to detect language

These are currently user facing errors, but are not localized. This adds the
ability for these messages to be localized.

This implements all pending specs, and adds additional coverage for the
following functionality:

* Normal status creation
* Creating a reply status
* Creating a sensitive status
* Creating a status with spoiler text
* A status with no spoiler text gets an empty string for spoiler text
* Creating a status with custom visibility
* Creating a status for an application
* Processing mentions
* Processing Hashtags
* Pinging PuSH hubs
* Crawling links
* Attaching media

There are currently not specs for the two media validations that are performed
by `PostStatusService`. This adds specs for the validations that ensure that you
cannot attach more than four files, and that a status cannot have both image and
video attachments.