Bug 14918: Remove C4::Dates from circ/pendingreserves.pl

Bug 14918: Remove C4::Dates from circ/pendingreserves.pl

This patch uses Koha::DateUtils instead of C4::Dates and Date::Calc. It
also sent DateTime objects to the template, which use the TT plugin to
display them.
If an invalid dates is entered, the default date is picked.

Test plan:
1/ Go to Home > Circulation > Holds to pull
2/ Verify that the the filter and the list behave as before
3/ Enter invalid dates and confirm that you do not get a software error

Counter patch works as expected and is a much cleaner solution.
Signed-off-by: Marc Veron <veron@veron.ch>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>