Bug 14783: Change pickup location from opac.

Bug 14783: Change pickup location from opac.

This patch allows users to change the  pickup location for their holds
from the opac. A syspref (OPACAllowUserToChangeBranch) controls at what
stage a hold can be changed.

To test:
1. Set up holds with diffrent statuses for a patron (pending, waiting,
   in transit, suspended)
2. No pickup locations for any hold should be able to be changed.
3. Turn on and off the different options under
   OPACAllowUserToChangeBranch. Make sure that only the corresponding
   holds can be changed from the opac. Check eg in the staff client that
   pickup location has changed.
4. The available pickup locations should respect any transfer
   restrictions. (Same as the
   holds list for a biblio in staff client)
5. For an in-transit hold: Check in the item at the original pickup
   location.
6. Note that it will be redirected to the new location.

Sponsored-by: Lunds Universitetsbibliotek
Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Barbara Johnson <barbara.johnson@bedfordtx.gov>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>