Add selective audio to API (Local deafen)

In short, It'd help greatly for the ability to local deafen (Have someone be unable to hear you)
This could be by default (everyone hears you, except who you deafen) or could be an opt-in (everyone can't hear you, except who you allow)
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This could be restricted to just bots, unless others like the idea of an individual local deafen.

However, It'd be so useful for:

• MusicBots (Opt-In system instead of blaring songs to everyone)
• Announcements (Server wide, or role-based)
• Group Games (Deafen people that lost a match)
• Secrets (Maybe you don't need to pull someone to another channel anymore) 

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Thoughts are appreciated - I had it in mind for Music, but it would open up so many possibilities c:

-Elite