Merge or update STAC notebooks 📑

[robbibt]

We currently have two STAC-related notebooks:

• This one that shows how to use odc-stac: https://docs.dea.ga.gov.au/setup/gis/stac.html
• This one that shows how to browse STAC metadata and load data from STAC URIs: https://docs.dea.ga.gov.au/notebooks/Frequently_used_code/Downloading_data_with_STAC.html

We should review these notebooks and see if we can either combine them, or update the "Downloading_data_with_STAC.ipynb" notebook to also include examples of using odc-stac