Add `timeout` argument to methods that invoke RPCs

[erny-powel]

gRPC supports it, and it's useful.

@tnoczyns-volue thoughts?

[tnoczyns-volue]

It is useful indeed. One of the potential approaches would be to add this timeout as an argument to Connection classes when initializing to avoid extending every single Connection and Session method that calls RPC. But I'm fine with both options.