Typespec Vscode extension should bundle the init logic

[timotheeguerin]

Right now it seems like it tries to use the local version/install a global compiler.

This has a few issues

• for the local case it's kinda useless as you most likely don't need to init if you already installed dependencies
• for the global case it forces to support n*m version of something that doesn't really matter.
  It also is polluting the user environment which is something we shouldn't do if they didn't ask for it

The extension should just call to the scaffold function and bundle that logic