If media_attachments are not loaded, SQL query is the same, but
the #exists? method performs SQL query even if preloaded

* Store home feeds for 7 days instead of 14

Reduces workload for status fan-out to active followers

* Fix test for user model

* 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

* 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 structure for lists

* Add list timeline streaming API

* Add list APIs, bind list-account relation to follow relation

* Add API for adding/removing accounts from lists

* Add pagination to lists API

* Add pagination to list accounts API

* Adjust scopes for new APIs

- Creating and modifying lists merely requires "write" scope
- Fetching information about lists merely requires "read" scope

* Add test for wrong user context on list timeline

* Clean up tests

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

slightly optimized FanOutOnWriteService again

adjusted to allow choosing it, yet

FanOutOnWriteService. The only recipient-specific part on them
is reblogged/favourited. But since only newly created statuses
appear on them, it is safe to assume that both attributes would
be false

redis-backed "mentions" timeline as redundant (given notifications)

Fix #233, fix #268

Fix #289 - don't download avatar unless the URL is http/https
Fix #293 - reblog/reblogged is now boost/boosted

during Fan Out On Write to load less stuff into memory

Fetching atom extracted from FetchRemoteAccountService and FetchRemoteStatusService
into FetchAtomService. Mentions of the constant "http://activityschema.org/collection/public"
skipped as it's not a real URL/user.

as well as formatting of content

in the pool, adding a throttle of 60rpm per IP, adding mini profiler, adding
admin status to users

and atom feed generation to some extent, as well as the way mentions are
stored

simplify FanOutOnWriteService, add /api/accounts/lookup method

fix tests (the recorded Salmon fixture expects LOCAL_DOMAIN to be something
specific unfortunately)