Support for current Notebook Launcher from Datascience

[mmcky]

@AakashGfude we need to see how much of the datascience launcher could be supported at the theme layer

https://datascience.quantecon.org/python_fundamentals/control_flow.html#net-present-values-and-asset-pricing

then click on "settings" next to launch Notebook.

Please consult @DrDrij on styling if needed. Thanks.

[mmcky]

@AakashGfude I have added some comments (re: design) here

QuantEcon/lecture-datascience.myst#66 (comment)

[mmcky]

@AakashGfude with the subfolder path -- can it just be added to the root address that we provide through the config?

Or is the subfolder after master in the url?

[mmcky]

@DrDrij will work on integrating the settings and launcher into the modal (as per comments on datascience linked above)

[mmcky]

fixed by #130