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

config/locales/cy.yml

@@ -115,10 +115,6 @@ cy:
       most_recent_ip: IP diweddaraf
       no_limits_imposed: Dim terfynau wedi'i gosod
       not_subscribed: Heb danysgrifio
-      order:
-        alphabetic: Allfabetig
-        most_recent: Diweddaraf
-        title: Trefnu
       outbox_url: Allflwch URL
       perform_full_suspension: Atal
       profile_url: URL proffil