Enable photometry downloads

[bfhealy]

Feature Summary
We currently have code to make and upload photometry (within fritz.py, called by scope_upload_classification.py). It would also be helpful to have the ability to programmatically download photometry.

Usage / behavior
This functionality could be implemented within scope_download_classification.py, toggled by an optional keyword. It should save the user's requested photometry locally.

Implementation details
This may need to be implemented in the section of the code that loops over each individual source. I am not aware of a current way to download photometry in bulk for multiple sources.

[mcoughlin]

@bfhealy Theo has code here for this: https://github.com/Theodlz/skyportal-dumps/blob/main/dump_skyportal.py#L741 that should be easy enough to incorporate.

[bfhealy]

In fritz.py, get_lightcurves_via_coords and get_lightcurves_via_ids serve this purpose.