* Remove most behaviour disparities between blocks and mutes

The only differences between block and mute should be:

- Mutes can optionally NOT affect notifications
- Mutes should not be visible to the muted

Fix #7230
Fix #5713

* Do not allow boosting someone you blocked

Fix #7248

* Do not allow favouriting someone you blocked

* Fix nil error in StatusPolicy

* Adjust policy to allow boosting own private toots

* Add ability to reblog private toots from dropdown menu

* Add moderator role and add pundit policies for admin actions

* Add rake task for turning user into mod and revoking it again

* Fix handling of unauthorized exception

* Deliver new report e-mails to staff, not just admins

* Add promote/demote to admin UI, hide some actions conditionally

* Fix unused i18n

* Add status destroy authorization to policy

* Create explicit unreblog status authorization