The existing configuration was partially compatible with Ricochet's,
but not enough to actually be useful. It also required a bunch of
boilerplate code to copy data between configuration data structures,
internal data structures, and RPC data structures.
Protobuf conveniently supports encoding messages to JSON, and we already
need to store most data (e.g. contacts) in protobuf structures. This
commit changes the configuration to be a protobuf JSON serialization of
the Config message, which can directly reuse RPC messages like Contact.
Additionally, the RWMutex-based configuration type was a deadlock
waiting to happen. There is now a read-only clone of the configuration
available atomically at any time. Writers need an exclusive lock on the
ConfigFile object, which commits its changes to disk and readers on
unlock.
The default address will be set from the environment, or fall back to
trying 127.0.0.1:9051. There is now an API to allow this to be
overriden as well.
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