Merge "res_pjsip: Create human friendly serializer names."

include/asterisk/res_pjsip.h

res/res_pjsip.c

res/res_pjsip_messaging.c

res/res_pjsip_outbound_registration.c

res/res_pjsip_pubsub.c

res/res_pjsip_refer.c

res/res_pjsip_registrar.c

res/res_pjsip_session.c

res/res_pjsip_transport_websocket.c