Setup private extraction workflow

[kvantricht]

Once #263 an #264 are done, we can setup the general workflow that users can follow to manage their private collection(s) extractions into locally organized geoparquet files. Result of this should be:

• general CLI workflow that can be used outside notebooks
• demo notebook showing how all this works
• documentation on how to monitor extractions, what to do in case of failure, what to do to resume, ...