Protections: configurable actions

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**Is your feature request related to a problem? Please describe.**
We have a room with 4k+ users. Some of them are pretty fast typers. We are currently using the `BasicFloodingProtection` protection to buy us some time, when no moderators are around and someone starts flooding the room. The feature works great, but occasionally, the bot bans someone who was just typing really fast.

**Describe the solution you'd like**
We would appreciate, if the bot could be configured to take different actions, especially for that one protection. For example:

- The user could be muted instead of banned (or whatever)
- The bot could send a configurable message to the room (`/me ...`), explaining, why the user has been muted (10 messages in the last minute) and that the moderators of the room will lift the restriction after review or so

For us, muting would be the best option. We don't need to change this on the fly, so having those options available in the config file would make use happy.

**Describe alternatives you've considered**
We thought of disabling the feature entirely, but we would rather not. Users are currently not too happy about the current situation either.

Start by locating BasicFloodingProtection and the configuration handling it uses. Define the configurable moderation action and optional room message, then verify that the protection can mute rather than ban and that the configured explanation is sent when the limit is reached.

Written by the indexing model from the issue text.