### Description
Currently the rtpengine_query function stores some values in predefined avps. I would like to have access to the whole output returned by the query to rtpengine. Sample provided at: https://github.com/sipwise/rtpengine#query-message
### Possible Solutions / Expected behavior
Introduce a new avp which stores the full output in json format.
https://www.kamailio.org/docs/modules/devel/modules/rtpengine.html#rtpengine...
Closed #2130.