closes #6573

Fixes #5485

closes #6533

closes #6490

closes #6465

closes #6456

* Adopt pronto suggestions

Signed-off-by: Lukas Matt <lukas@zauberstuhl.de>

closes #6398

and refactor coding style according to pull request comments

(#5324)

and correct test syntax
#5324

(#5324)

* add a class for checking pod connectivity
* extend pod model to handle new functionality
* add an admin frontend to list pods and re-trigger checks manually
* add a daily worker to run through all the pods
* add unit tests for most of the new code

closes #6310

closes #6307

closes #6286

closes #6243

Squashed commits:

[ada0f09] Remove favorites from Posts table

closes #6208

* .well-known/social-relay - to serve subscription preferences to relays
* Workers.deferred_dispatch relay carbon copy functionality for outbound sending

See discussion here: https://www.loomio.org/d/9vpoe0UR/public-post-federation#comment-730911 and spec here: https://wiki.diasporafoundation.org/Relay_servers_for_public_posts

closes #6060

closes #5945