Bug 11565 - decreaseLoanHighHolds needs Override

Bug 11565 - decreaseLoanHighHolds needs Override

This patch allows the high holds loan length decrease to be overridden
either by a checkbox that remembers its setting during a series of
checkouts, or by a one time use override checkbox that will show
in the warning popup if a checkout is affected by high holds.

Test Plan:
1) Set up a checkout that will be affected by decreaseLoanHighHolds
2) Attempt to check out an item
3) Check the override checkbox
4) Note the checkout date is not reduced
5) Return the item
6) Start a new checkout for the patron
7) Check the "Don't decrease lean length based on holds" checkbox
8) Check out the item
9) Note you are not warned about the high holds decrease
   and that the checkout length is not reduced

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Christopher Brannon <cbrannon@cdalibrary.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>