Add new endpoint providing cloud-coverage for all overlapping images (bounding-box or polygon) within a data-range

use-case: agri domain showing best image within a certain date period or all images with cloud-coverage < x percent

new endpoint

• input: date range, geometry, product
• output: list of dates including necessary metainformation (like cloud-coverage)

as discussed this new endpoint may not necessarily be a WPS process

TBD: cloud-coverage may be inferred by Scene Classification (as available in S2L2A -> Sen2Cor generated SCL layer) or additional vector cloud-masks, propose to initially start by considering SCL=8 (medium) and SCL=9 (high) and SCL=10 (cirrus) of Sen2Cor generated product (as this should be available out of the box with Element84 bucket) and refine over time