IDE shouldn't require global cadl to be installed

[timotheeguerin]

[Error - 11:31:11 AM] Cadl server exectuable was not found: 'cadl-server' is not found. Make sure either:
 - cadl is installed globally with `npm install -g @cadl-lang/compiler'.
 - cadl server path is configured with https://github.com/microsoft/cadl#installing-vs-code-extension.

it the compiler is accessible locally it should be able to auto resolve it.

[nguerrera]

I think we were tracking this in #1041 and I was supposed to fork off an issue for a nicer init without global install, but we can reverse that so this one tracks resolving local server without using global server and that one tracks the nicer init.

[nguerrera]

We had pri: 0, estimate: 5, November for this, removing that from #1041 and putting it up for re-triage.

[timotheeguerin]

est: 5