Bug 36595: Added email address field to the holds queue table

Bug 36595: Added email address field to the holds queue table

To test:
1. Make sure that the system preference ‘HidePatronName’ is set to
   ‘Show’
2. Select a patron that has a primary email address set in their
   contact information.
    1. Place a hold for that patron
3. Build the holds queue: perl /kohadevbox/koha/misc/cronjobs/holds/build_holds_queue.pl
4. Check the holds queue and notice that the patron column includes the
   patron’s email
5. Click on the hyperlinked email. It will open a new email with the
   subject of "Hold item: (your biblio title)"
6. Disable the ‘HidePatronName’ system preference
    1. Check the holds queue again and notice that no contact
       information can be seen for the patron
7. Sign off and have an amazing day :D

Signed-off-by: Matt Blenkinsop <matt.blenkinsop@ptfs-europe.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>