jsonld context cleanup

Closes #369

See merge request pleroma/pleroma!434

Small jsonld refactor

See merge request pleroma/pleroma!433

qvitter notifications: add new "read notifications" API

See merge request pleroma/pleroma!431

Runtime configuration

See merge request pleroma/pleroma!430

Mastodon API: relationships without id param

See merge request pleroma/pleroma!432

This copies Mastodon API behaviour & fixes Mastalab app.

Remove Access-Control-Allow-Origin in pleroma.nginx

See merge request pleroma/pleroma!424

Related to #85

Everything should now be configured at runtime, with the exception of
the `Pleroma.HTML` scrubbers (the scrubbers used can be
changed at runtime, but their configuration is compile-time) because
it's building a module with a macro.

Unify Mastodon Login with OAuth login.

See merge request pleroma/pleroma!429

Runtime configured router

See merge request pleroma/pleroma!426

Get rid of Pleroma.Config in favor of Application

See merge request pleroma/pleroma!428

Same API as the old Pleroma.Config

This removes duplication in the login code.

Discussed in pleroma/pleroma!426 (comment 7232)

Use the same example domain and use it as variable

See merge request pleroma/pleroma!423

Runtime emojis: Fix wrong return when finmoji is disabled

See merge request pleroma/pleroma!427

Runtime configured emojis

See merge request !425