feat: manually specify ice candidates

[Aboot-face]

Problem

Current project is using a containerized environment, but specifying network=host is not always possible for some organizations.

Fix

I have enabled manually specifying ice candidates which allows for the use of a loadbalancer service or similar to get around the problem with container NAT networks.
ice_candidates is an optional parameter in the config.json file specified by:

if len(Storage.ServerICECandidates()) > 0 {
    options.ICECandidates = Storage.ServerICECandidates()
}

This is passed to vdk NewMuxer as it directly supports specifying ice candidates.