Add details about Quarto CLI MIT licensing vs other tools in quarto-dev/quarto like visual editor

[cderv]

From quarto-dev/quarto#727, there is clarification to make on the licences for tools in quarto-dev/quarto monorepo (probably since Quarto CLI moved to MIT)

This would be good to add a paragraph in our Licence page in the website about them https://quarto.org/license.html

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It would be really helpful to clarify that on your license page here:
https://quarto.org/license.html

Especially as the site documents the vscode, positron, and rstudio extensions under quarto.org, and the footer on all of the pages says that they are licensed MIT, referencing the github org (which includes this repo), not the CLI package specifically.

Originally posted by @rowanc1 in #727