Bundle default fallback compiler with vscode extension

[nguerrera]

Once we're in the marketplace, it will be really nice if basic scenarios can work without installing a cadl compiler via npm.

We should bundle a language server+compiler with the extension and update the logic so that if it doesn't find a compiler, it uses the one inside the package.

[timotheeguerin]

the one thing with this is then this only work if you need no libraries at all (or those also needs to be bundled with)

[nguerrera]

See also #711. I was thinking you'd get the core language working, then you do import "@foo/bar" then Ctrl+. on the squiggle and it offers to npm install it for you.

That seems like it would make a nice demo that doesn't involve command line installs. But, I was hoping this might unblock using vscode.dev directly, but we wouldn't be able to install libs in there would we?

[timotheeguerin]

I see, that would make sense