Bug 22809: Move "INVOICE" from template to a slip

Bug 22809: Move "INVOICE" from template to a slip

Just as bug 22761 moves the "Fee receipt" to the ACCOUNT_CREDIT slip, we need to move the "INVOICE" to an ACCOUNT_DEBIT slip.

Test Plan:
1) Apply this patch set
2) Restart all the things
3) Use the "print" button beside a *fee*
4) You should not see any difference from before the patches were applied

Signed-off-by: Liz Rea <wizzyrea@gmail.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>