MultistateSampler - make iteration logging info level instead of debug?

[IAlibay]

Discussing things with @mikemhenry today, it would be quite useful if we could get a general sense of run progression for MultistateSampler derived classes without getting all the debug information that usually comes along with it.

I am specifically referring to the following two logging events:

https://github.com/choderalab/openmmtools/blob/main/openmmtools/multistate/multistatesampler.py#L683

https://github.com/choderalab/openmmtools/blob/main/openmmtools/multistate/multistatesampler.py#L770

Alternatively something like an optional progress bar (tqdm? extra verbose argument for run?) would be really useful (and possibly less noisy than dealing with logger outputs).

[ijpulidos]

This sounds like something we definitely should improve. Thanks for the feedback! I don't know if @mikemhenry is already working on this, but I'm happy to give this a try, probably some day next week if it isn't that urgent.