better "harmful command" support

[amyulating]

im too lazy to type

[kzndotsh]

Can you explain this a little better?

[HikariNee]

What they mean (from what I can infer), is that every server has a local table where they can define custom "harmful commands" and custom messages to show.

Though, I disagree with the in-memory database part, it'll start eating memory very quickly. Ideally, we want the fetch sequence running in a separate thread so it doesn't block things.