Bug 31562: Treat flags as other borrower fields

Bug 31562: Treat flags as other borrower fields

Rather than generate a custom hash for these fields, we should treat them as other borrower data fields

To test:
 1 - Edit a patron, note the 'Lost card' and 'Gone no address' fields
 2 - Edit syspref BorrowerunwantedField
 3 - Set gonenoaddress and lost as unwanted
 4 - Edit patron, the fields remain
 5 - Apply patch
 6 - Edit a patron, fields are hidden
 7 - Unhide one of the fields
 8 - Edit a patron and confirm it shows and saves correctly
 9 - Unhide the other field
10 - Confirm it can be edited and saved

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>