Integrate client into loadgen

[xzfc]

Instead of having standalone executable client.py (or C++ version, see #112) that runs arbitrary workload, we could integrate the client into loadgen itself. This would simplify running the power measurement on the SUT side, and allow us to measure in more environments, e.g. mobile.

We considered this option in the past (2020-12-11), but decided to postpone it after round 1.0. Probably should be done in the inference repo.

Estimate time of implementation: 3-4 weeks.

• Analyze loadgen codebase to understand what is the best way of integration
• Create minimal working prototype that can connect to the server
• Integrate all necessary features

[s-idgunji]

I would like to propose that we only take this on, if any other higher priority issues are resolved and if we can fix this by v1.1 freeze date.