Bug 31036: Treat SIP00 that same as CASH

Bug 31036: Treat SIP00 that same as CASH

SIP00 is the code for CASH transactions that have taken place on a SIP
client.  Cash management treats CASH type transactions as a special case
for banking and register requirements. This patch brings SIP00 in line
with the CASH handling code of cash management.

Test plan
1) Enable cash management with 'EnablePointOfSale'
2) Enable cash registers with 'UseCashRegisters'
3) Add a cash register via 'Administration > Cash registers'
4) Make some payments against the ash register in the staff client
5) Attempt to make a payment via a SIP client without having associated
   a cash register to the SIP account config
5a) This should now fail
6) Attach the cash register to the SIP account used above
6a) Payment should now work again on SIP transactions
7) Look at the cash register details page for the cash register
7a) 'Bankale' should now include cash from both SIP and Staff client
sales

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Sally <sally.healey@cheshiresharedservices.gov.uk>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>