vango: Enhancements to the "all" func

The intention is for this to be used as a demonstration of how
Vanadium discovery+RPC+security shows value in the face of constantly
moving devices with changing network connectivity (turning WiFi on/off,
turning bluetooth on/off)

Specifically:
- The "All" function continuosly advertises and scans
- Whenever it finds a new peer, it sends an RPC to it
- It prints out the identity of the remote user (as a result of the
  authentication protocol) and the address of the underlying channel
  (tcp/bluetooth etc.) used to actually communicate.

Next I intend to play a lot with this app to find bugs/areas of
improvement for the underlying RPC and discovery code.

MultiPart: 1/2
Change-Id: I433f3cff5c964ceb84c92d9e378b2502b41efd00
4 files changed