Add description for S5P-L3GRD-KdBLUE-DAY

[dmoglioni]

@AparicioSF Description to be filled here for S5P-L3GRD-KdBLUE-DAY. Additional information available also on the Copernicus S-5P Mapping Portal.

[AparicioSF]

• Markdown/description update
• JSON update
• Add link to STAC browser