Auto-detect automated raids

[emmiegit]

Futaba should, if configured, be able to take some action if it detects a possible raid. Specifically, if it sees messages with identical contents posted more than 4 times by different or the same user in rapid succession, it will trigger raid settings for that guild. This will trigger one of a few responses:

For small raids (different members < 5, messages/sec < 10/5):

• mute roles are applied to all members
• staff are notified

For large raids:

• an override to the channel is added for the member role, preventing sending messages
• users who are still posting who meet the qualifications of "small raid" above are given the mute role