Please create pfs_utils git repo

There are PFS-specific routines which could be useable by several actors, or by the DRP. Oh, the routines for building telescope and actor FITS header sections. Or mapping hostnames to actor instance names. Or building pathnames and URLs. Since they are PFS-specific but not ICS-specific I don't think that tron_actorcore is the right place.

So pfs_utils, please.