Communication Library Investigation

[Maxusmusti]

Look into what communication library backends (NCCL, GLOO, MPI, etc.) are currently supported via the SDK and submission to Ray (and direct MCAD potentially), and what we may need to change if anything not currently supported would be desirable.

Likely the three we are interested in at the moment (old article, but interesting):
https://mlbench.github.io/2020/09/08/communication-backend-comparison/