Bug 33159: Simplify ES handling and fix zebra handling

Bug 33159: Simplify ES handling and fix zebra handling

Before this patch we used two indexes for the thesaurus values, we can
simply index both needed fields into a single index and just form the
search correctly.

This patch also ensures we pass the 'thesaurus' vlaue for the heading
directly to the query builder - for zebra it goes through, and for ES
we convert it to the expected code.

This patch also moves the necessary mappings out of the user definable
mappings and hardcodes them. There is precedent for this with
'match-heading', it ensures matching works as expected

To test:
1 - Follow previous test plan in Zebra and ES

Signed-off-by: Phil Ringnalda <phil@chetcolibrary.org>
Signed-off-by: Frank Hansen <frank.hansen@ub.lu.se>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>