v1.0.4: Implement a logging module. (#77)
* Implement a logging module.
This can safely set the logging verbosity level on a server using stdr package.
Implement basic unit tests and client/integration tests.
All client side support in sanssh to do this on the proxy itself.
Wire into proxy as an RPC it'll serve in addition to /Proxy.Proxy
This means we need to add interceptors for unary RPCs here now too.
* Rename from logging to sansshell as the service breakdown so it's obvious this is internal state.
* Fix client command to be sansshell instead of logging