This changes the REST API to return unicode domains in the `acct`
attribute instead of punycode, and to render unicode instead of
punycode on public HTML pages as well.
Fix#7812, fix#12246
* 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
