* Remove Salmon and PubSubHubbub endpoints

* Add error when trying to follow OStatus accounts

* Fix new accounts not being created in ResolveAccountService

* Add moderation warnings

Replace individual routes for disabling, silencing, and suspending
a user, as well as the report update route, with a unified account
action controller that allows you to select an action (none,
disable, silence, suspend) as well as whether it should generate an
e-mail notification with optional custom text. That notification,
with the optional custom text, is saved as a warning.

Additionally, there are warning presets you can configure to save
time when performing the above.

* Use Account#local_username_and_domain

* Improve overview of accounts in admin UI

- Display suspended status, role, last activity and IP prominently
- Default to showing local accounts
- Default to not showing suspended accounts

* Remove unused strings

* Fix tests

* Allow filtering accounts by IP mask

* Add render_views in more places

* Delegate methods from account to user with allow nil true, so that admin accounts show view renders when missing a user

* Use actual account instances in authorize follow controller spec