Bug 30611: Add ability for staff to send password reset emails

Bug 30611: Add ability for staff to send password reset emails

This patch adds the ability for staff with the edit_borrowers permission
to send password reset emails to users.

The staff initiated password reset has it's own notice,
STAFF_PASSWORD_RESET, and the reset link produced has an extended
timeout of 5 days, as apposed to the usual 2 day limit.

Test plan
1) Apply patch and run the database update
2) Login to the staff client with a user who has the 'edit_borrowers'
   permission.
3) Note that a new, 'Send password reset' option appears under the
   'More' menu on the patron details page.
4) Clicking the button will queue the STAFF_PASSWORD_RESET notice and
   redirect the user to the Notices tab.

Signed-off-by: Sally <sally.healey@cheshiresharedservices.gov.uk>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>