Add note about mdns ws
Add note about mdns ws

Add a note about the discovery possibility on the provider side.

sbender9/signalk-server-node,sbender9/signalk-server-node,SignalK/signalk-server-node,webmasterkai/signalk-server-node,SignalK/signalk-server-node,sbender9/signalk-server-node,SignalK/signalk-server-node,webmasterkai/signalk-server-node,webmasterkai/signalk-server-node,SignalK/signalk-server-node