docs: Create asset summaries investigation (#150)

* feat: Enable Jupyter in Nix shell

* feat: Demonstrate asset datetime summary investigation

Looks like it would be simple to extend the `summaries` property to
allow asset-specific summaries by referring back to the definition of
the `summaries` property.

You can try the notebook yourself by running `nix-shell --run 'jupyter
lab extensions/linz/notebooks/asset-datetime-summary.ipynb'`.

* feat: Demonstrate asset datetime summary investigation

Looks like it would be simple to extend the `summaries` property to
allow asset-specific summaries by referring back to the definition of
the `summaries` property.

You can try the notebook yourself by running `nix-shell --run 'jupyter
lab extensions/linz/notebooks/asset-datetime-summary.ipynb'`.

* Revert "feat: Demonstrate asset datetime summary investigation"

This reverts commit 3ebeb37.

Co-authored-by: Bill Nelson <[email protected]>

Author: l0b0