Standalone CLI: Investigate bundling more of the cli

[timotheeguerin]

Follow up fromhttps://github.com//pull/5794

Currently the standalone cli will download the latest compiler(similar to running npm install -g @typespec/compiler and use that version which in turn might use the local one if available.

It would be good to see if we can bundle better so the cli is basically the version of the compiler package minus the "compiler" part.

For this we need:

• to be able to bundle the package manager used in tsp install in a single file(which is a problem right now with npm arborist)
• reorganize the compiler so that we can bundlke only the cli part(without the compiler logic)
  • if you try to tsp compile . without having a local compiler installed it should fail
  • decide if we always still try to load the local compiler if available or only for the compile stage.