DIAMETER: Introduce and rework some AVP templates

All the AVP ecosystem in DIAMETER is quite a mess. There's AVPs defined
in several different specs, sometimes even with the same name and
different AVP code and vendor.
Hence, as we add more templates it becomes important to start using the
prefix in order to differentiate where they come from.

Change-Id: Iec7c51dae136629d6b754de4dd798e988ac51f6b
diff --git a/pgw/PGW_Tests.ttcn b/pgw/PGW_Tests.ttcn
index e1f49ab..1041898 100644
--- a/pgw/PGW_Tests.ttcn
+++ b/pgw/PGW_Tests.ttcn
@@ -361,7 +361,7 @@
 					tr_AVP_Multiple_Services_Credit_Control(content := superset(
 						tr_AVP_Requested_Service_Unit,
 						tr_AVP_Used_Service_Unit,
-						tr_AVP_3GPP_QoS_Information,
+						tr_AVP_PCC_3GPP_QoS_Information,
 						tr_AVP_GI_3GPP_RatType(rat_type)
 					)),
 					tr_AVP_3GPP_ServiceInformation(content := superset(
@@ -410,7 +410,7 @@
 						tr_AVP_Requested_Service_Unit,
 						tr_AVP_Used_Service_Unit,
 						/* tr_AVP_3GPP_Reporting_Reason, can be sometimes inside UsedServiceUnit */
-						tr_AVP_3GPP_QoS_Information,
+						tr_AVP_PCC_3GPP_QoS_Information,
 						tr_AVP_GI_3GPP_RatType(rat_type)
 					)),
 					tr_AVP_3GPP_ServiceInformation(content := superset(
@@ -460,7 +460,7 @@
 						/* tr_AVP_Requested_Service_Unit, Only in INIT and UPDATE */
 						tr_AVP_Used_Service_Unit,
 						tr_AVP_3GPP_Reporting_Reason(FINAL),
-						tr_AVP_3GPP_QoS_Information,
+						tr_AVP_PCC_3GPP_QoS_Information,
 						tr_AVP_GI_3GPP_RatType(rat_type)
 					)),
 					tr_AVP_3GPP_ServiceInformation(content := superset(