Create a modal for "edit this page on Github"

[Firgrep]

New users people to github might be overwhelmed by it, so we want to make sure that support is visible.

The "edit this page on Github" in the table of contents on the right panel should open a modal that gives the option to continue to github or go to the contributions page to learn about what Github is and how to use it.

We'll probably need to turn off the default link in Nextra from the theme config and build our custom component based off of their solution, except that it opens the modal instead of directly linking. Nextra exposes a useConfig hook, if I recall correctly, which should expose the dynamic github link.

[PatrickLarocque]

If you would like to assign me to this issue, my ongoing PR can be associated 😊

[Firgrep]

Pat's got busy, so if anyone else wants to pick this up! Just make a comment :)

[JMielbrecht]

@Firgrep I'll take it! :)

[Firgrep]

@JMielbrecht MUI has a really nice Dialog component you could use for the modal functionality