Improve ingame moderation for admins (#3678)

## Description:

Players with the `admin` flare can now kick players from any game
(including public lobbies), not just the lobby creator in private
lobbies.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

w.o.n

resources/lang/en.json

@@ -882,6 +882,7 @@
   "kick_reason": {
     "duplicate_session": "Kicked from game (you may have been playing on another tab)",
     "lobby_creator": "Kicked by lobby creator",
+    "admin": "Kicked by an admin",
     "host_left": "The host has left the lobby."
   },
   "send_troops_modal": {