This commit makes it so that all API wrapper methods under state will
ignore errors returned from the cabinet setters. This is because an
intermittent error from the state shouldn't shadow the actual result
from the Discord API.
This commit gets rid of all the code that previously managed different
voice sessions in different guilds. This is because there is rarely ever
a need for this, and most bots that need this could do their own
keeping.
This change, although removes some features off of the package, adds a
lot of clarity on what to do exactly when it comes to connecting to a
voice channel.
In order to make the migration process a bit easier, an example has been
added which guides through using the voice.Session API.