LP#1175400 Check for over allocation from funding source

LP#1175400 Check for over allocation from funding source

When allocating money from a funding source to a fund it is possible to
allocate more money to the fund than exists in the funding source.  This
code adds a check with a dialog that stops the user from over allocating
from a funding source unless they choose an override option.

TODO: Need to add a permission check to allow the override.

Signed-off-by: Liam Whalen <liam.whalen@bc.libraries.coop>
s#	Open-ILS/web/js/ui/default/acq/financial/view_funding_source.js~