Bug 13412: Allow configuration of auto-created authorities

Bug 13412: Allow configuration of auto-created authorities

This patch add 2 new system preferences:
- GenerateAuthorityField667
- GenerateAuthorityField670

When Koha creates authority records from biblios, use these preferences instead of the hard-coded "Machine generated authority record." and "Work cat." values.

Test plan:
    1. Make sure AutoCreateAuthorities and BiblioAddsAuthorities are enabled in the system preferences
    2. Go to Home › Cataloging › Add MARC record and add a new record
    3. Fill in the required fields and add a name in the 100$a field. Note the name, and add the new record.
    4. run rebuild_zebra.pl -a
    5. Go to Home › Authorities and search for the name you entered in 100$a
    6. Select details and look at the 667 and 670 fields. They should default to the hard-coded values.
    7. Apply patch, run update database
    8. Edit the new GenerateAuthorityField667 and GenerateAuthorityField670 system preferences
    9. Do 2-6 . Now the 667 and 670 fields should be what you entered in the system preferences.

Thanks for testing

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Works well, no errors

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>