Automatically protect rooms after being invited

[bkil]

If a user invites the bot to a room (and after a few minutes have elapsed #80 ), the bot could

• introduce itself briefly,
• give a link to the source, its operator and/or a room where to ask for bans,
• remind that it will be able to see all messages and history,
• declare that it needs to be elevated to a permission level that allows it to remove messages, kick, ban,
• and optionally a level that allows changing server ACL as well.

Those who are not familiar with it but see it in another room may be tempted to invite the bot to their own room for protection, without knowing how it works.