Add CLI task for rotating keys (#8466)

* If an Update is signed with known key, skip re-following procedure

Because it means the remote actor did *not* lose their database

* Add CLI method for rotating keys

    bin/tootctl accounts rotate [USERNAME]

Generates a new RSA key per account and sends out an Update activity
signed with the old key.

* Key rotation: Space out Update fan-outs every 5 minutes per 1000 accounts

* Skip suspended accounts in key rotation

lib/mastodon/emoji_cli.rb

@@ -13,7 +13,7 @@ module Mastodon
     option :suffix
     option :overwrite, type: :boolean
     option :unlisted, type: :boolean
-    desc 'import PATH', 'import emoji from a TAR archive at PATH'
+    desc 'import PATH', 'Import emoji from a TAR archive at PATH'
     long_desc <<-LONG_DESC
       Imports custom emoji from a TAR archive specified by PATH.