add admin command to force demote a local user from a room

Signed-off-by: strawberry <strawberry@puppygock.gay>

src/admin/user/mod.rs

@@ -79,6 +79,13 @@ pub(super) enum UserCommand {
 		room_id: OwnedRoomOrAliasId,
 	},
 
+	/// - Forces the specified user to drop their power levels to the room
+	///   default, if their permissions allow and the auth check permits
+	ForceDemote {
+		user_id: String,
+		room_id: OwnedRoomOrAliasId,
+	},
+
 	/// - Grant server-admin privileges to a user.
 	MakeUserAdmin {
 		user_id: String,