closes #6354

* 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 #6307

closes #6223

* .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

remove old webfinger/hcard generation code

this fixes #5143

remove old webfinger/hcard generation code

this fixes #5143

closes #5945

- move to contacts.js
- use json
- move to aspects_controller
- add route
- rewrite test
- fix css in chrome

GET requests don't get any CSRF protection by Rails,
thus these sensitive actions should be better protected.

Thanks to @tomekr for the report.

related to diaspora/jsxc#77

* create a new token on a new session
* delete the current token on session exit

On default none is permitted to chat with you.
You have to set extra privilege for an aspect.

Add Sidetiq webview to the Sidekiq monitoring panel

Add rake task maintenance:queue_users_for_removal
This basically just triggers an immediate run of the normal maintenance remove old users functionality that is normally (if enabled) scheduled to run once a day via sidetiq

Add extra safety when checking for user removal due to inactivity.
Now also user.last_seen will also be checked to make sure a user will not be removed in the event that the Devise rememember me login functionality has stopped the users remove_after timestamp from being removed.

Add initializer for maintenance job.
Add warning about mail being disabled if remove_old_users maintenance is enabled.

* introduce new presenters and extend the functionality of the BasePresenter
* add a handlebars template for the profile sidebar, render it everytime we need to update
* introduce a 'aspect_membership:update' global event

If enabled, terms of service link will be shown in sign up page.

* thanks to @maxwell for the initial work on this

port admin pages to bootstrap
* improve user view on admin search page
* add 'close account' link to each user in the search results
* keep the same blue color for the admin menu

some refactoring of the routes and the admin code
* try to be more RESTful (possibly)
* use a 'UserSearch' model for search parameters and querying

add changelog entry

* Renamed PostReport to Report
* Added report button to SPV
* Updated rspec

refs diaspora/diaspora#4732
refs diaspora/diaspora#4710
refs diaspora/diaspora#4711
refs diaspora/diaspora#4517