use `projection`/`proj` STAC extension for basically any asset to be aware of georeferencing for any asset even if non existent

[Scartography]

Use as many of STAC projection extension as possible to have readily available information about georeferencing data.

The assets groups are currently missing this information

Also for products that are not projected like Sentinel-1 data use like proj:epsg: none to make sure that it states that the data is not (properly) geocoded!

[Scartography]

Regarding the datasets with no projection and using GCPs, for any ideas try to comment on: https://github.com/stac-extensions/projection or maybe there is time for a separate STAC extension.