slapos_pdm: Reorganise tests for reduce code duplication and for speed up tests

Define smaler Unit Tests files is preferrable to make distribution easier for the test nodes.

master/bt5/slapos_pdm/TestTemplateItem/portal_components/test.erp5.testSlapOSPDMUpgradeDecisionSkins.xml → master/bt5/slapos_pdm/TestTemplateItem/portal_components/test.erp5.testSlapOSPDMCreateUpgradeDecisionSkins.xml

@@ -14,7 +14,7 @@
         </item>
         <item>
             <key> <string>default_reference</string> </key>
-            <value> <string>testSlapOSPDMUpgradeDecisionSkins</string> </value>
+            <value> <string>testSlapOSPDMCreateUpgradeDecisionSkins</string> </value>
         </item>
         <item>
             <key> <string>description</string> </key>
@@ -24,7 +24,7 @@
         </item>
         <item>
             <key> <string>id</string> </key>
-            <value> <string>test.erp5.testSlapOSPDMUpgradeDecisionSkins</string> </value>
+            <value> <string>test.erp5.testSlapOSPDMCreateUpgradeDecisionSkins</string> </value>
         </item>
         <item>
             <key> <string>portal_type</string> </key>