[OStatus] adds status to pleroma instance if the url given is a status

See merge request !1002

[#757] Add mix task to delete user's activities

See merge request !1008

Replace `Repo.get_by` with existing functions

See merge request !1010

priv/static/images: Add pleroma-tan

See merge request !913

MastoAPI 2.6.0 `force_login` option

Closes #734

See merge request !999

Replace `Repo.get(Module, id)` with `Module.get_by_id(id)` where possible

See merge request !1009

Fix account lookup for nicknames beginning with numbers

See merge request !1003

CI speedup: split into proper stages to benefit from parallel execution

See merge request !1007

router: Add fake identity proof endpoint

See merge request !1006

Add default mail adapter settings to config

See merge request !994

Small documentation improvements

See merge request !1001

[ci skip]

Fix dead links in README.md and add note about new docs site

See merge request !1000

[ci skip]