Bug 21520: More complex OAI sets mappings

Bug 21520: More complex OAI sets mappings

Currently, the rules used to create OAI sets are processed with the 'or'
boolean operator between each rule.

This patch allows to use 'or' or 'and' between the rules.

The evaluation of the rules is done according to the boolean operators
precedence: AND has a higher precedence than OR.

For example:

A and B or C and D

will be evaluated as follow:

(A and B) or (C and D)

Test plan:

 - Apply the patch
 - Apply the atomicupdate
 - Prove t/db_dependant/OAI/AndSets.t
 - Check that existing mappings still work
 - Try modifying existing mappings
 - Try creating new mappings
 - Check that the boolean operators precedence is correctly taken into account

Signed-off-by: Michal Denar <black23@gmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>