Bug 34657: Merge cataloging plugins for UNIMARC 123d, e, f, and g

Bug 34657: Merge cataloging plugins for UNIMARC 123d, e, f, and g

This patch removes some UNIMARC cataloging plugins which were
essentially duplicates of each other and renaming the remaining version
to reflect that it's for use with multiple subfields.

UNIMARC 123$d, e, f, and g can all be filled with
unimarc_field_123defg.pl

It's easiest to test if you have UNIMARC sample data. In KTD, run
'reset_all_unimarc'

- Apply the patch and run the database update process.
- Go to Cataloging and create or edit a bibliographic record.
- Under tab 1, look for tag 123.
- Test the plugin link for subfields d, e, f, and g
  - In each case the popup window should have the heading "UNIMARC field
    123d/e/f/g builder"
  - Fill out the form each time and confirm that the values are copied
    to the correct field in the MARC editor window.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>