Bug 11126 - Make the holds system optionally give precedence to local holds

Bug 11126 - Make the holds system optionally give precedence to local holds

This feature will allow libraries to specify that, when an item is returned,
a local hold may be given priority for fulfillment even though it is
of lower priority in the list of unfilled holds.

This feature has three settings:
* LocalHoldsPriority, which enables the feature
* LocalHoldsPriorityPatronControl, which selects for either tha patron's
  home library, or the patron's pickup library for the hold
* LocalHoldsPriorityItemControl, which selects for either the item's
  holding library, or home library.

So, this feature can "give priority for filling holds to
patrons whose (home library|pickup library) matches the item's
(home library|holding library)"

Test Plan:
1) Apply this patch
2) Run t/db_dependent/Holds/LocalHoldsPriority.t

Signed-off-by: Joel Sasse <jsasse@plumcreeklibrary.net>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>