Redesign admin accounts index (#9340)

* 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

app/controllers/admin/accounts_controller.rb

@@ -94,8 +94,8 @@ module Admin
         :local,
         :remote,
         :by_domain,
+        :active,
         :silenced,
-        :alphabetic,
         :suspended,
         :username,
         :display_name,