Bug 31565: [21.11.x] Fix datatables searching escape for exact search

Bug 31565: [21.11.x] Fix datatables searching escape for exact search

To test:
1. Add a new patron category with categorycode 'TEST_CAT'
2. Add a patron to category 'TEST_CAT'
3. Go to Patrons search view
4. Under "Search for patron" filters, filter by category you created at step 1
5. Click Search
6. Observe no results
7. Apply this patch and reload
8. Repeat 3-5
9. Observe expected result

Double check tests from Bug 30393 still work as expected:

10. Go to the cities page
11. Add two cities:
   - 'Cordoba %'
   - 'Buenos Aires _'
   - 'London \'
12. Use the column search on the name, alternating _, \ and % as the query
=> SUCCESS: Filtering works correctly!

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Bug 31565: Escape datatables MySQL special characters only in LIKE queries

Escaping \ yields no results when performing exact search in datatables.
This patch adds MySQL special character escaping only to LIKE searches.

To test:
1. Add following categorycode 'TEST\CAT' by SQL
insert into categories (categorycode,description) values ('TEST\\CAT', 'TEST\\CAT');
2. Add a patron into TEST\CAT category
3. Go to patron search
4. Limit search by category TEST\CAT
5. Observe no results
6. Apply patch
7. Refresh patron search page
8. Limit search by category TEST\CAT
9. Observe Koha redirecting you to patron you chose in step 2

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Bug 31565: (QA follow-up) Remove support for _ as wildcard in -like queries

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
(cherry picked from commit 8fead08cedd8eb56601f5be66c8f9056966759bd)
Signed-off-by: Arthur Suzuki <arthur.suzuki@biblibre.com>