Bug 21246: Extend the 'Last patron' navigation feature to 'Last 10 patrons'

Bug 21246: Extend the 'Last patron' navigation feature to 'Last 10 patrons'

This retains the "last patron" link, but extends it to add a dropdown
containg the last 10 patrons.

A future enhancement to control how many patrons to retain would
complement this well.

1) Enable showLastPatron
2) Visit two patrons details pages
3) Note "Last patron" link displays and links to the last visited patron
4) Log out
5) Apply this patch
6) Log in
7) Visit the patron details page for a few patrons
8) Note the "Last patron" link behaves as is did previously
9) Note the split button has a pulldown with the other previous patrons
10) Verify that only the last 10 patrons are retained in the pulldown
11) Verify that if you visit a patron who is already in the list
    they get moved to the top of the list

Signed-off-by: Sam Lau <samalau@gmail.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>