Use non-stdlib type stubs bundled with typeshed

[connernilsen]

Currently, Pyrefly doesn't use the type stubs bundled with typeshed for non-stdlib stuff. We should implement that by including them in the compiled Pyrefly binary and using them when looking up site package path entries.

One thing to keep in mind while implementing is that we can't blindly follow the spec here and add it as import item 6, we need to probably update the site package path import function to look for an import and use it if we can't find another import OR we can find another import, but it doesn't have a py.typed file.