I understand that this change is quite unreadable and hard to review, sorry for forgetting to do atomic commits. This patch does not change too much content wise, it just
* Gets everything from gitlab wiki
* Removes some specific gitlab hacks
* Formats all documentation file names to be in snake case so they look the same way as our code does

Add more user filters + move search to its own module

See merge request pleroma/pleroma!982

Fix muting reblogs tests

See merge request pleroma/pleroma!984

Fix missing announces in MastoAPI home timeline

Closes #762

See merge request pleroma/pleroma!983

Closes #762

MastodonAPI: Add GET /api/v1/apps/verify_credentials

See merge request pleroma/pleroma!981

Do not federate instance avatar

Closes #759

See merge request pleroma/pleroma!977

Mastodon 2.7.2 instance attributes (registrations, languages)

See merge request pleroma/pleroma!979

Mastodon-based auth error messages. User#auth_active?/1 refactoring.

See merge request pleroma/pleroma!978

Increment replies_count (MastoAPI)

Closes #756

See merge request pleroma/pleroma!974

Remove ActivityRepresenter

See merge request pleroma/pleroma!980

Add an `id desc nulls last` index to notifications

See merge request pleroma/pleroma!975

fix up missing announcements with preloads

See merge request pleroma/pleroma!972

add overriding truncated_namespace condition for truncating paths for digital ocean

See merge request pleroma/pleroma!969

Serve non-public activities in /api/v1/favourites

Closes #648

See merge request pleroma/pleroma!970

Fixes #648

mrf/keyword_policy.ex: Fix when summary == nil, do not whitelist content == nil

See merge request pleroma/pleroma!968

Ignore compilation warnings for undefined module :eldap

See merge request pleroma/pleroma!956

preloaded object normalization

See merge request pleroma/pleroma!967