log bans to modlog channel

[Huuums]

this is a PR to fix #45 partially.

Unfortunately it's not possible to get the info of who banned the user.

It doesn't seem to be possible to log kicks specifically. There is a guildMemberRemove event but that seems to trigger everytime a user leaves or gets kicked. You can't distinguish the two.

I tried to use the deleted property on the GuildMember object that gets passed in the guildMemberRemove event but it seems to be false every time.

[Huuums]

So after Iggy pointed out that you can in fact figure out who banned the person via getting the Auditlogs I improved the ban messages.

I also used the Auditlog functionality to figure out if a user was kicked whenever a user leaves the server. While it works as intended I feel that this is rather hacky and the Bot needs this permission so that it can work. see yellow arrow.

I'm open to more feedback :)

[vcarl]

Closing cuz this just never got merged and is now out of date 😔 I believe there's (still) an issue with ban tracking where the audit log API does not reliably fire events, when I've tested in the past a reasonably high % of bans wouldn't get caught. I saw similar when testing a deleted message tracker but worse, something like 40-60% of deleted messages wouldn't fire a gateway event. This was also opened at a time when I personally was paying ~ the least attention I ever have to Reactiflux — sorry for letting this wither on the vine