* Remove Salmon and PubSubHubbub endpoints
* Add error when trying to follow OStatus accounts
* Fix new accounts not being created in ResolveAccountService
* Prevent silenced local users from notifying remote users not following them
This is an attempt to extend the local restrictions of silenced users to the
federation.
* Add tests
* Add tests for making sure private status don't get sent over OStatus
* 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
* Add test for temporary account resolving failures in ProcessMentionsService
* Fix processing of mentions to already-known remote accounts on temporary failures