Bug 30663: Add x-koha-override options to /suggestions

Bug 30663: Add x-koha-override options to /suggestions

This patch adds the x-koha-override header parameter to the route that
is used to create suggestions, POST /suggestions.

The idea is that adding suggestions will be rejected under certain
conditions unless x-koha-override is passed with appropriate values. The
added overrides are:

* any
* max_total
* max_pending

Tests are added for the expected behavior.

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