Implement a high TRL QA engine (i.e. usable) on top of PCAPI filter-chains. As a reminder, an example chain that filters by envelop, date and exports as geojson is:

filter=envelope,date,format&bbox=-2.33,33,0.10,34.44&start_date=20151101_12:00:00&end_date=20160105_12:00:00,frmt=geojson

Since all filters share parameters we need to avoid name collisions. All new QA parameters should be prefixed by the filter name and underscore e.g. filter=los,los_bearing=-1.

The old PCAPI filters keep their existing names.