Bug 23354: Add receipting to Pay page

Bug 23354: Add receipting to Pay page

This patch adds receipt printing to the new Point of Sale pay page.

Test plan:
1) Apply patch and run database update
2) Enable automatic receipt printing via the `` system preference.
3) Make a payment for an item via the new POS pay page.
4) Note that a receipt printing dialogue is shown automatically after
   payment.
5) Note that a new notice is available under tools where you can alter
   the content of the receipt.
6) Signoff

Sponsored-by: PTFS Europe
Sponsored-by: Cheshire Libraries Shared Services
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>