Bug 24490: Clarify wording and function of Purchase Items link on POS

Bug 24490: Clarify wording and function of Purchase Items link on POS

This patch changes the wording of the links on the POS side menu

To test:

1) Apply the patch
2) Check that the links on the left hand side of the screen read "Configure cash registers" and "Configure items for purchase"
3) Click both links to ensure you are taken to the relevant config pages.

Signed-off-by: Andrew Fuerste-Henry <andrew@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>