Add stx_map2fits to the ssw software

[hayesla]

There's this code stx_fits2map.pro that available from the datacenter https://datacenter.stix.i4ds.net/pub/misc/stix_imaging/stx_map2fits.pro, however it would be nice if this were available directly through the stix ssw software.

Basically to save a STIX map to a FITS file with the correct header info

[samaloney]

Yea we should defo add some version of this but it gets complicate as the fits file position info is based on date-avg by definition, but the imaging software should be using the spice data from the actual imaging time via the aux-ephemeris files. Most of the time they should be that different but not always.

[hayesla]

do you mean the fits file position info within the original pixels file?

[afbattaglia]

Thanks for bringing this up, @hayesla. We have had a discussion during the co-location with @samaloney and @FredSchuller. Since I have made the last modifications to this file, I can look into it, optimize it, and do a pull-request in the near future.