This implements a handler for inbound contact request connections,
taking advantage of the synchronous Process API.
This is largely untested code at the moment.
This includes connection management and enough to compile, but doesn't
reimplement most of the protocol messages and functionality yet. There
are problems noted throughout the code, also.
Improved parts of the conversation implementation, moved the
conversation event monitor to Identity, added event monitor
population, and other minor changes.
Also, slightly refactor Ricochet to be an interface to get the various
top-level components, and let the implementation define it (such as
backend's RicochetCore RPC type)
John Brooks