Notify admins when bot is @-mentioned

[heftig]

Is your feature request related to a problem? Please describe.
Users requesting moderation from the bot aren't heard.

Describe the solution you'd like
The bot should send a message containing @room to its admin room when it is mentioned in another room. This reaction should be rate-limited.

Describe alternatives you've considered
Users can still contact individual moderators but this defeats the anonymity of the bot's actions.

[turt2live]

@room is maybe a bit strong, but batching or general noise from the bot could be helpful to bump the activity of the management room. A config option would be valuable.