Introduce identify and rendezvous network protocols

[mycognosist]

The next step in our networking efforts is to extend the peer discovery functionality of aquadoggo.

The libp2p rendezvous protocol (spec) provides a discovery mechanism by allowing peers to register themselves with a server and query the addresses of other peers. The rendezvous protocol is often paired with the identify protocol (spec) to provide a means for rendezvous client nodes to learn their external IP address (necessary knowledge for registering with a rendezvous server).

We are aiming for a single node (aquadoggo) which can run as a rendezvous server or client, depending on CLI configuration.

A rendezvous client needs the address and peer ID of a rendezvous server in order to connect, register and query.