Prune / mass delete endpoint

[Darkflame72]

Add a prune or mass delete endpoint which would allow the mass deletion of x number of messages in a channel. This will be especially useful to moderation bots to cleanup after spam or other situations. It will also stop there being a lot of requests to mass delete messages and instead can be a single one.

[DeclanChidlow]

https://developers.revolt.chat/developers/api/reference.html#tag/messaging/DELETE/channels/{target}/messages/bulk