Bridging Calls

Implement the ability for a user to bridge multiple channels in one discord server, so that for example, when there are multiple groups, the users can be split into separate channels whilst still talking, then be separated. Potentially allow announcements cross voice channel.

Also allow for bridging between discord servers, so that 2 separate groups of people can have bridges made between servers. For if a friend has friends in another server who want to communicate with friends on your server, without having to hop server.