We're close to hooking up new Razor to MVC. This is a set of enabling
'quick fix' changes to resolve some blockers to using Razor.Evolution in
the product.
Main issues:
- Types not public enough - anything in the .Legacy namespace is still
slated from 'improvement'
- Wrong references. We don't want .Workspaces in MVC, so moving the heavy
lifting of TagHelper discovery to CodeAnalysis.Razor.