Add support for hang statuses

[codeofandrin]

Summary

This PR adds support for hang statuses, which can be set while being in a voice channel. This is typically displayed via Right now, I’m - on the client.

Since there's no Discord PR yet, it's on draft. Though, it's partially rolled out already (33%).

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, ...)

[Rapptz]

The status of this feature has really irked me but is also the reason why it's iffy to merge these without a corresponding docs PR. This has gone through 3 different implementations API wise, and as far as I can tell right now it's been removed from clients entirely. So I'm not sure about the state of this one.

[codeofandrin]

The status of this feature has really irked me but is also the reason why it's iffy to merge these without a corresponding docs PR. This has gone through 3 different implementations API wise, and as far as I can tell right now it's been removed from clients entirely. So I'm not sure about the state of this one.

Yes, that's why I set this PR on draft. It's also unclear what happen with voice statuses, because on the server where I tested hang statuses, the voice status feature was entirely gone.