Bug 24478: Use `EnablePointOfSale` preference

This patch adds the `EnablePointOfSale` preference to the accounting tab
on the preferences editor and ties the display of the Point of Sale
module to it.

Test plan:
1) Enable both `UseCashRegisters` and `EnablePointOfSale` preferences.
2) Ensure you are a superuser or your user has the
   takepayment permission.
3) The Point of Sale module should be present on your staff home page
   with the above configuration, otherwhise it should not.

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>

koha-tmpl/intranet-tmpl/prog/en/modules/admin/preferences/accounting.pref

@@ -1,12 +1,5 @@
 Accounting:
     Policy:
-        -
-            - pref: UseCashRegisters
-              default: no
-              choices:
-                yes: "Use"
-                no: "Don't use"
-            - " cash registers with the accounting system to track payments."
         -
             - pref: AccountAutoReconcile
               choices:
@@ -19,3 +12,18 @@ Accounting:
                   yes: "Do"
                   no: "Don't"
             - automatically display a print dialog for a payment receipt when making a payment.
+    Features:
+        -
+            - pref: UseCashRegisters
+              default: no
+              choices:
+                yes: "Use"
+                no: "Don't use"
+            - " cash registers with the accounting system to track payments."
+        -
+            - pref: EnablePointOfSale
+              default: no
+              choices:
+                yes: "Enable"
+                no: "Disable"
+            - " the point of sale feature to allow anonymous transactions with the accounting system. (Requires UseCashRegisters)"

koha-tmpl/intranet-tmpl/prog/en/modules/intranet-main.tt

@@ -80,7 +80,7 @@
                     <div class="col-xs-6">
                         <ul class="biglinks-list">
 
-                            [% IF ( Koha.Preference('UseCashRegisters') && CAN_user_cash_management_takepayment ) %]
+                            [% IF ( Koha.Preference('EnablePointOfSale') && Koha.Preference('UseCashRegisters') && CAN_user_cash_management_takepayment ) %]
                             <li>
                                 <a class="icon_general icon_pos" href="/cgi-bin/koha/pos/pay.pl"><i class="fa fa-shopping-cart"></i>Point of sale</a>
                             </li>