Unify the client code

[ankitbhrdwj]

Client code is scattered across multiple files, and the same code(request packet formation, request Tx, and response Rx, etc.) is used multiple times in different clients, which requires manual changes in each client file(whenever needed).

• Design the client layout, maybe in a way where standard code is shared across all the clients, and we only need to implement a trait per client.
• Allow both open-loop and closed-loop load generation from the client
• Add a few test cases, maybe automate the YCSB(or some other) benchmark to compare the performance across commits?