Following RFC-575 and DM-17029, Update the 5 reference catalogs in /datasets/refcats/htm/ to have nJy fluxes using meas_algorithms/bin/convert_refcat_to_nJy.py

More details at https://community.lsst.org/t/photocalib-has-replaced-calib-welcoming-our-nanojansky-overlords/3648

The code convert_refcat_to_nJy.py updates the catalogs from v0 to v1 refcats in place. So before converting, make a copy of all directories remained in v0, and keep those copies around for people using the stack older than w_2019_14.

For consistency of the HSC-RC2 DM-18300 run, don't start the actual converting before the w_2019_14 run is done.