Implement threads for client.cpp and server.cpp

[BasicAlgorithm]

• Two threads. (1st) for CreateRequest and (2nd) for ProcessResponse(int connectionFD)

[mgonnav]

On the server:

• Listens on a port waiting for connections. When a connection arrives, launch a thread for that connection that waits for requests and processes them.

On the client:

• Once the connection goes through, creates a thread that waits for responses from the server.