Add voice channel status events and permission

[codeofandrin]

Summary

This PR adds the events and permission for the voice channel status.

Note: The implementation of the endpoint to set the voice channel status is seperated into a second PR (https://github.com/Rapptz/discord.py/pull/9603) because it cannot be merged due to the experiment lock, which this PR already can.

Related PR: https://github.com/discord/discord-api-docs/pull/6398/

Checklist

• [x] If code changes were made then they have been tested.
  • [x] I have updated the documentation to reflect the changes.
• [ ] This PR fixes an issue.
• [x] 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, ...)

[codeofandrin]

I used the constructor instead of an _update method to assign the status because a channel update would overwrite self.status to None since the status is not in the payload of a channel update. In the client however, if you edit the channel the status gets reset which I assume is a UI bug (see this comment: https://github.com/discord/discord-api-docs/pull/6398#issuecomment-1752029443)