Set up basic logging utils

[vincekurtz]

It'd be nice to have some helper functions for doing basic logging with tensorboard, wandb, etc. This would probably live in utils/logging_utils/ or something like that. The main thing is to simply define a callable like that does whatever you want with the metrics, e.g.,

def progress(num_steps, metrics)
    # print some stuff
    ...
    # save some stuff
    ....

see discussion in #36.

\cc @ivandariojr