Support asymmetric ICE

[dbason]

Describe the feature

Stunner is a kubernetes native STUN/TURN server. We can use it in symmetric ICE mode, but a nice to have would be being able to configure it in asymmetric ICE mode when mediamtx is also running inside kubernetes. Would you be interested in accepting a pull request to enable this? I believe the changes would need to be in the signalling side so we can respond to the client with ICE configuration without using it in the server.

[dbason]

The best way I can see to do this is leave the js portion that sends the ICE servers and add a boolean to the ice server configuration object; like clientOnly.