Add DEBUG mode

[ibro45]

🚀 Feature Request

Add debug mode that can be controlled with an env variable. Let it print out information like input, target, pred data type and shape before and after the forward, before and after each postprocessing step etc.

🔈 Motivation

When setting up the experiment it can be difficult to figure out where exactly the problem is in cases where there's a shape mismatch and similar.

[surajpaib]

This might also be a cool feature to add

[ibro45]

WANDB_SILENT env var should be 1 by default unless the user specified it or if the DEBUG is ON. Too many useless messages from it.