Simplify Migration to the Main Bot Instance

[SocksTheWolf]

Right now, if a bot is detected to be already added, then whatever bot is about to be added automatically leaves. This causes a problem because the sub bots should probably be the ones leaving, but this also complicates things because of how discord permissions work.

God what a pain discord permissions are. It would be good if we could just refresh and get everyone on the same instance, less work overall.

[SocksTheWolf]

The solution in #94 will likely conflict with us for a bit. We should probably make note of it (it'll just waste CPU cycles over a few days, not a huge issue but w/e).

Probably could just make a "recently_removed" table, and if we have detected you were previously activated on a different instance we just ignore importing any bans.

Yeah that'd probably do it.