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

[timotheeguerin]

Would note that currently we want to move away from actually being able to use the global compiler to compile as it fails as soon as you need libraries which is basically all the actual use case.

The advantage however of bundling the compiler is it would be an alternative to poc where it bundles the init logic. This might be a better approach, not sure.

TypeScript is bundled in VScode and while it has advantage I think it also often decide to use the wrong one and you get inconsitent errors between local build and the ide due to the ide using a different version.