Threads support

[Qsie]

New feature available through Discord's API v9 (Discord.JS v13), threads are effectively mini-channels that are temporary.

One possible use case includes separate threads per "session", where users can externally define each session as an event, or something that warrants a thread but not a full-borne channel.

Currently, updating to Discord.JS v13 does not allow the workaround of specifying the thread ID, which I thought may be possible but isn't after checking the documentation.