Move the address:port parsing code to the net helper. Add a default
address option.
Pass the interface address to protocol-simple and use this as the
default address for listening.
This makes sure that when the user passes tcp:3400 that we don't end up
publishing 0.0.0.0:3400 but the actual address of the interface we are
listening on so that the snapcast discover can use this to notify the
snapcast server.
Fixes#4093
The module detects remote snapcast servers and creates a new sink
with protocol-simple for each server.
It sets up a new stream on the server for the sink with JSON-RPC.
