Consider prompt to pip install jupyter

[juliasilge]

One thing I have tripped over many times when using a Python .qmd file is that I need the jupyter Python package installed to render it. I do see documentation at places like this:

https://quarto.org/docs/get-started/hello/vscode.html#basic-workflow

But it's actually not clear IMO that you need the jupyter package just to make Quarto work at all.

One idea to help here would be to detect that jupyter is not installed in the active/current Python and prompt to install it. We do this in the Positron Python extension for ipykernel, which is needed for the console to work.

See https://github.com/posit-dev/positron/blob/01b4b65925a4990c4048d6bbea9cfd2b2ae5bcc4/extensions/positron-python/src/client/positron/session.ts#L241-L245

It's possible that we build in some check here in the Quarto extension that then calls to Positron to do the check, since we have all that infrastructure already set up and I don't believe this extension does.