Review the summary object content

[tloubrieu-jpl]

💡 Description

We want the summary object to contains these fields:

Source	name	example	status in v1.2
request parameters	url	https://pds.nasa.gov/api/search/1/products	missing
	q	"pds:Identification_Area.pds:title eq "InSight HP3 Radiometer Experiment Derived Product:hp3_rad_der_00014_20181211_073042"",	ok
	keywords	insight	missing
	start	0	ok
	limit	10	ok
	sort	["lid"]	not implemented
	fields	["lidvid", ...]	missing
response parameters	hits	14	ok, returns number of results beyond the pagination limit
	took	294	could add unit ?
	properties	["lid", "lidvid", "ops:Label_File_Info/ops:file_ref", ...]	not ok, should return available properties beyond the pagination limit

See discussion on #256 (comment)