Bug 35579: Cache authorised value lookup by MARC field

Bug 35579: Cache authorised value lookup by MARC field

This patch adds a "get_descriptions_by_marc_field" method
which caches AuthorisedValue descriptions when searched by
MARC field, which is used when exporting MARC to CSV.

Test plan:
0. Do not apply the patch yet!
1. Go to http://localhost:8081/cgi-bin/koha/tools/csv-profiles.pl
2. Add a CSV profile with the default values and using the following for the "Profile MARC fields":
000|001|003|005|006|007|008|010|015|016|020|022|040|050|082|100|110|111|130|240|243|245|246|247|250|260|300|336|337|338|440|490|500|501|505|520|530|600|610|611|630|648|650|651|690|700|710|711|856|887|942|995|952|952$c
3. Create a new List
4. Add all the database's bibs to that list using SQL like the following (where the shelfnumber equals the number for your list):
insert into virtualshelfcontents (shelfnumber,biblionumber,borrowernumber) select 1,biblionumber,51 from biblio;
5. Go to that list in the staff interface
6. Download that list using your CSV profile
7. Apply the patch
8. koha-plack --reload kohadev
9. Download that list using your CSV profile
10. Note that the output is the same, but that the output completes much more quickly after applying the patch

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>