Bug 23893: Special care for booleans

Bug 23893: Special care for booleans

This patch acknowledges the fact that in D8 the Mojo::JSON->true and
Mojo::JSON->false values don't translate into integers when passed to
DBIC. It works correctly on D9 onwards, but we haven't formally
deprecated Jessie. This is adding back this translation, in the right
place now that all mappings code has been integrated into
Koha::Object(s) directly.

To test:
1. Apply this patch
2. Run:
   $ kshell
  k$ prove t/db_dependent/Koha/Object.t
=> SUCCESS: Tests pass!
3. Sign off :-D

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