Implement RPC tester
Implement an RPC tester that allows us to check the network performance of the RPC layer. Later, this can then be used as a baseline to GekkoFS, allowing us to understand and optimize for a given environment combined with automatic tests to find the best configuration.
The tester should include server and client code for both Margo and Hermes.
TheRPC tester server can also be added to the start scripts #52.