SOL003 VNF Lifecycle Management - Implementation of deltas between v3.3.1 and v2.7.1

This merge request refers to the implementation of deltas between v3.3.1 and v2.7.1 of SOL003 VNF Lifecycle Management Interface.

@lynchpi @aelken @matsuurat @carignani @sayama @kraja @zulfiqar @zafar

Deadline for review: Friday 12th March 2021 @6pm CET

Review period elapsed: approved !

SOL003/VNFLifecycleManagement-API/IndividualVNFSnapshot.robot

@@ -102,6 +102,7 @@ DELETE Individual VNF Snapshot
     ...    Post-Conditions: VNF Snapshot deleted
     DELETE individual VNF Snapshot
     Check HTTP Response Status Code Is    204
+    Check Postcondition VNF Snapshot Resource Is Deleted
 
 DELETE Individual VNF Snapshot - Conflict
      [Documentation]    Test ID: 7.3.1.41.9
@@ -114,4 +115,5 @@ DELETE Individual VNF Snapshot - Conflict
     ...    Post-Conditions: none
     DELETE individual VNF Snapshot - CONFLICT
     Check HTTP Response Status Code Is    409
-    Check HTTP Response Body Json Schema Is    ProblemDetails
\ No newline at end of file
+    Check HTTP Response Body Json Schema Is    ProblemDetails
+    Check Postcondition VNF Snapshot Resource Existence
\ No newline at end of file