Feat: Guild Scheduled Events

[Daniel-Worrall]

This adds Mappings, API methods, Permissions, Websocket, Caching for the recently released Guild Scheduled Events

Relevant docs are here.

The commits have been separated by each aspect for ease of review.

This has been tested through development, but some bugs could remain as I haven't done a final test of each method and there are no specs.

There are various decisions I made that should be discussed before being merged, like the start time on a newly created event default, the caching code for event users, and perhaps others.

Please reach out in the discord for any small questions, and follow up on the issue on what was discussed, to keep the spam low but the information relevant.

[Manu590]

thanks too bro

[Daniel-Worrall]

Ready for review/merge