feat: Allow and document external environments

[dmadisetti]

fixes #13

@brettc would this be alright?

[brettc]

Thanks. That looks good. So if I understand correctly I have 3 options:

• add the deps to the yaml of the notebook
• add the deps to the _quarto.yaml
• add external-env: true to my yaml

In the first two cases, marimo will create a .env with uv
In the third case, it will assume everything is available.

[dmadisetti]

Correct!

[brettc]

Thanks for the fast reply. And for marimo -- a godsend after faffing with ipynb for so long.

[dmadisetti]

Don't be shy filing issues. I'm glad it is working for you