fix(voice): zero-fill discovery packet, add IP discovery timeout (#205) - #19

…labahaha#205)

Found a couple of issues when it comes to using UDP (and one on voice in
general):
- If the UDP doesn't respond, the connection doesn't properly time that
out
- It *seems* that some voice servers may reject our packet if it has
some garbage data from using `Buffer.allocUnsafe`, although I can't
exactly pinpoint the voice servers doing this, it seems to be newer
ones.
- When using the VoiceConnectionManager to join channels, the disconnect
error doesn't propogate up and rather always uses the "Disconnected"
error.

Also noticed that the voice connection timeout uses the gateway options
instead of its own, and i didn't make a UDP timeout option yet. Maybe it
is time to make a new `voice` options prop.

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Co-authored-by: TTtie <me@tttie.cz>