Better handle STAC products from MPC

[remi-braun]

Right now, MPC STAC products handling is not really well tested, due to a lack of usecase.

However, it is likely to change, so it could be good to debug it thoroughly:

• Fix and test in CI geometry functions (extent, footprint)
• Fix async issues in notebooks
• Use obstore instead of stac-asset (see this issue)
• ... ?