Bug 37436: Move EmailPatronWhenHoldIsPlaced to Holds policy sysprefs

Bug 37436: Move EmailPatronWhenHoldIsPlaced to Holds policy sysprefs

This patch moves the EmailPatronWhenHoldIsPlaced system preference
from Circulation > Patron restrictions to Circulation > Holds policy.

To test:
1. Apply patch
2. Go to Administration > System preferences > Circulation > Holds
   policy
   --> EmailPatronWhenHoldIsPlaced should be right after
       emailLibrarianWhenHoldIsPlaced

Signed-off-by: hebah <hebah@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>