Include support for Copernicus Dataspace collections

[Felipe Carvalho]

Describe the requested improvement

Catalogue documentation: https://documentation.dataspace.copernicus.eu/APIs/STAC.html

Provide access to data :

• SENTINEL-1-RTC
• SENTINEL-1 (GRD)
• SENTINEL-2 (L2A)

Associated sits API function
sits_cube()

Additional context
Implement specific functions to STAC for Copernicus dataspace.