LP#1398107: Alert when autodeleting a title with holds on it.

LP#1398107: Alert when autodeleting a title with holds on it.

Add a new "TITLE_HAS_HOLDS" event that we pass up to the user
if any non-canceled, unfulfilled title hold targets a bib that
would otherwise be silently deleted with holds canceled.

Also, retarget any holds pointing to a bib that is automatically
deleted after removing its volumes/copies to the destination bib
if this is the last copy.

Signed-off-by: Chris Sharp <csharp@georgialibraries.org>
Signed-off-by: Rogan Hamby <rogan.hamby@gmail.com>