Missing Guild properties for many events

Created by: uwx

Summary

Many gateway events, despite not necessarily being tied to a guild, have guild_id properties, and these are usually discarded by the lib. They should be exposed in order to match the API. In addition, some of these events may also contain skeleton objects created in their handler, which should have their guilds filled in too.

Details

I'm not going to write a conclusive list of every single event that is missing this property, but if you go on the Gateway docs page and search guild_id?, most of those are not mapped.