TT#75200 pv_headers: rework

* don't try to detect branch every time
* reduce use of dynamic memory
* rework reply scenario, keep reply_counter in xavp
* hook to branch event too

Change-Id: I0adf97d4cb2d214e80fae48f8fdc643c1a644cc6

debian/patches/series

@@ -75,6 +75,8 @@ upstream/avpops-add-avp_subst_pv.patch
 ### relevant for upstream
 sipwise/fix_error_in_cfgt_module.patch
 sipwise/pv_headers-store-To-info-in-xavp_parsed_name.r-on-re.patch
+##
+sipwise/pv_headers-full-rework.patch
 #
 ### Don't just put stuff in any order
 ### use gbp pq import/export tooling to help maintain patches