Add moderation warnings (#9519)

* 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

config/locales/it.yml

@@ -429,12 +429,6 @@ it:
       confirmed: Confermato
       expires_in: Scade in
       topic: Argomento
-    suspensions:
-      bad_acct_msg: Il valore di conferma non corrisponde. Stai sospendendo l'account giusto?
-      hint_html: 'Per confermare la sospensione dell''account, inserisci %{value} nel campo qui sotto:'
-      proceed: Continua
-      title: Sospendi %{acct}
-      warning_html: 'La sospensione dell''account comporta la cancellazione <strong>irreversibile</strong> dei suoi dati, che comprendono:'
     title: Amministrazione
   application_mailer:
     notification_preferences: Cambia preferenze email