Use logging instead of print in codebase

[chanind]

Currently, logging info is output using print(), but this makes it hard to control the verbosity level of the output, and cannot distinguish between debugging / info statements and warnings / errors. For instance, in sae_training/config.py, creating a config object prints a lot of statements, but these are a mix of debugging / info / warnings, and would be better suited to using the Python logging module.

[anthonyduong9]

I can work on this this week.

[anthonyduong9]

@chanind there are many tests and .ipynb files with print(). It's not clear to me if print() or logging is better there, and for tests, if we should have print() or logging at all. What do you think?

[chanind]

I feel like print is fine for jupyter notebooks, and agree, unit tests shouldn't have print statements ideally - prints in unit tests should be deleted. Maybe benchmark tests are OK to have print statements since we don't really run those except manually and rarely.