formatter: 'recjson' format addition
- Adds general implementation of 'recjson' using formatter engine. (addresses #1908)
- Adds an upgrader recipe for the new output format.
Signed-off-by: Eirini Psallida <eirini.psallida@cern.ch>
Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>