Generalize BYOL training/predicting code

[ajtritt]

The train-byol and infer-byol commands are not generalized. Paths to the cropped image data have hardcoded directory paths in them, so they cannot be used with new data.

The following code segments will need to be addressed:

• https://github.com/lbl-cbg/lmcontrol/blob/main/src/lmcontrol/nn/byol.py#L125-L130
• https://github.com/lbl-cbg/lmcontrol/blob/main/src/lmcontrol/nn/byol.py#L146-L153
• https://github.com/lbl-cbg/lmcontrol/blob/main/src/lmcontrol/nn/byol.py#L205-L208