Bug 19494: Add reservedate to Holds awaiting pickup

Bug 19494: Add reservedate to Holds awaiting pickup

Add reservedate to report.
Change label "Available since" to "Waiting since".

Note: The table (already) crosses the boundaries of its container. Also
the vertical spacing for the first column (already) is not the same as the
others. (Adding the second date only makes it more visible.) These minor
design issues should be solved on another report.

Test plan:
[1] Go to Circulation, Holds awaiting pickup
[2] Note the additional column for reservedate.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Simon Pouchol <simon.pouchol@biblibre.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>