Add notebook demonstrating how to create a STAC collection for a virtual icechunk store

[jsignell]

This notebook is an improved version of: https://gist.github.com/jsignell/86236d7e5db70363f1c94a2ded0c2119 and demonstrates how to create a STAC Collection for a virtual icechunk store using the following extensions:

• Zarr STAC Extension
• Storage STAC Extension
• Datacube STAC Extension
• Render STAC Extension
• Virtual Assets STAC Extension

If the bucket that stores the virtual icechunk or the chunks themselves were not publicly accessible then you could also use the Authentication STAC Extension to specify how to access those buckets.

Closes #6

TODO:

• update to use virtual assets STAC extension (the virtual chunk container is a separate collection-level asset)
• add a notebook on how to create a STAC item for each legacy data file
• add a notebook on how to use the STAC collection-level metadata to access the data.

[jsignell]

Not sure who all will want to review, but since the workshop is coming up I thought I should at least mark this as ready for review. I am still planning on trying to put together an example on how to consume the collection-level asset.