Fwaas API Test Enhancement

Add Test to insert and remove firewall rule to firewall policy

-Create a firewall rule
-Create a firewall policy
-Insert a firewall rule to policy
-Validate the insertion of rule to policy
-Remove the firewall rule from policy
-Validate the removal of firewall rule from policy

Change-Id: I3c9711294e1e6323bdad4ff783de1ed19e133c1b
Merge "Fwaas API Test Enhancement"