Implement FGCM

[raphaelshirley]

Based on discussion:

Use 2Mass calibrators

Use FGCM as per LSST and use GAIA for astrometry - check what LSST are doing?

[raphaelshirley]

Making reference catalogues:

https://github.com/lsst-uk/lsst-ir-fusion/blob/master/dmu2/5_Make_ref_cats_VIDEO.ipynb

needs to be rerun for cdfs or move to fgcm