Improve the Get Started Flow for Positron

The current docs have a user download a document, open it in Positron, and give basic setup instructions (e.g. which packages to make sure they have installed).

I think we could do something much better. I.e. ideally a single command (that we could help a user run by providing a positron:// link in the docs) that initiates the flow below, so a user can get everything they need and have as a high a probability as possible that the first Quarto Preview on hello.qmd just works.

Flow:

• Offer a choice between R and Python.

• Create a new folder and populate it with the Get Started (language-specific) documents:

  • hello.qmd
  • computations.qmd
  • authoring.qmd

• Python only: a prompt to get create a virtual environment, and activate it.

• Check and prompt to install the packages required for Quarto:

  • Python: jupyter
  • R: rmarkdown

• Check and prompt to install the packages required for the Get Started documents:

  • Python: plotnine
  • R: tidyverse

• A guarantee (or check) that the interpreter Quarto will find is the same as the active one in the Console.