Automatic spam detection

[baabaablackgoat]

Automatically detecting spam and taking care of it.

This was moved from issue #26 to get a better overview.

This should involve a lot of customizability, so here goes:

• [ ] Detecting an influx of images from one user and deleting it.
• [ ] Detecting an influx of messages from one user within a short period of time, and deleting it.
• [ ] Allowing the botowner to set these thresholds himself "spam_embed": {"time":10s,"amount":10}
• [ ] Automatically distribute configurable punishments (like mute, kick, roleban, ban) Mastery Tasks:
• [ ] Taking care of bot spam - both own spam (this bot) and other bot calls.
• [ ] Whitelisting users and access values.