SOL002 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 SOL002 VNF LCM Interface.

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

**Deadline for review: Wednesday 3rd March 2021 @6pm CET

Review period elapsed: approved**

SOL002/VNFLifecycleManagement-API/IndividualVNFSnapshot.robot

@@ -18,7 +18,7 @@ POST Individual VNF Snapshot - Method not implemented
 GET Information about an individual VNF Snapshot - SUCCESSFUL
     [Documentation]    Test ID: 6.3.5.26.2
     ...    Test title: GET Information about an individual VNF Snapshot - SUCCESSFUL
-    ...    Test objective: The objective is to create a new VNF Snapshot resource
+    ...    Test objective: The objective is to GET information about an individual VNF Snapshot
     ...    Pre-conditions: none
     ...    Reference: Clause 5.4.24.3.2 - ETSI GS NFV-SOL 002 [2] v3.3.1
     ...    Config ID: Config_prod_VE