Bug 30077: Add system preference IntranetAddMastheadLibraryPulldown

Bug 30077: Add system preference IntranetAddMastheadLibraryPulldown

To test:
1. Apply patch, updatedatabase, restart_all
2. Search for the system pref 'IntranetAddMastheadLibraryPulldown'
3. Set it to 'Show'.
4. Go to any page that contains header search box and click on 'Search
   the catalog'.
5. To the left of the search bar you should see a dropdown for branches.
6. This should be defaulted to 'All libraries'.
7. In the dropdown choose any branch and do a search and make sure it is
   correctly limiting to that branch.
8. Try changing to a different branch and doing another search. It
   should correcrly limit to that branch BUT it should also default back
   to 'All libraries' for the next search.
9. Try selecting 'All libraries' from the top of the dropdown and make
   sure it is correctly searching all branches.
10. Turn on the system pref 'IntranetCatalogSearchPulldown' and make
    sure it looks nice with both of those dropdowns and functions when
    you use limiters from both dropdowns.

Signed-off-by: Sally <sally.healey@cheshiresharedservices.gov.uk>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>