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
3 files changed