Nuclei.Communication: Discovery process should be based on a URI only

[pvandervelde]

The discovery process currently requires the URI, the channel type and the endpoint ID. This limits the communication capabilities because in order allow the handshake process to start you first have to figure out what the endpoint ID is (which is based on the machine name and the PID). If the discovery would only provide a URI then the handshake process could determine the remaining information.

This would:

• Make the discovery process both simpler and more robust
• Allow more different discovery methods
• Separate the discovery layer from the protocol layer.

[pvandervelde]

Fixed in 0.7.2.0 (commits related to #3)