LP#1654534: Prevent loop that occurs when staff us 'place another hold' link

LP#1654534: Prevent loop that occurs when staff us 'place another hold' link

A hidden field that tracked the page the user was on before placing a hold was
inadvertently removed in another bug fix. As a result, if staff used the link
to place another hold on the same title, they were stuck in a loop where they
couldn't return to the source page after hitting the 'continue' button. This
commit restores that hidden field.

Also provides a fix so that hold labels used in the place another hold link
can be translated.

Signed-off-by: Kathy Lussier <klussier@masslnc.org>
Signed-off-by: Ben Shum <ben@evergreener.net>