Bug 16274: Limit the patron self registration to some libraries

Bug 16274: Limit the patron self registration to some libraries

Currently a patron can select a home library in the list of all
libraries defined in the system.
However some of these libraries might not accept self registration.
This patch adds a new pref to display only the allowed libraries.

Test plan:
0/ Apply the patch, do not fill the new pref
1/ Self register a new patron
=> All the libraries defined should be displayed in the "Home library"
dropwdown list
2/ Fill the pref PatronSelfRegistrationLibraryList with some of the
branchcode defined in the system
=> Self register a new patron and confirm that the dropdown list has
been filtered.

Sponsored-by: BULAC - http://www.bulac.fr/
Signed-off-by: Nicolas Legrand <nicolas.legrand@bulac.fr>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>