Complete moving our build away from machine state

[cartermp]

As of ~1 month ago, a rube-goldberg machine installation of machine dependencies were required to do anything in the Visual F# Tools. That won't be a thing soon. We want the following process to be all that is required:

1. Clone the repo.
2. Run build.

Related PRs:

#4023
#4005
#4004
#4002
#4001
#3995
#3992

[cartermp]

This is about as complete as it will get. We will depend on the .NET SDK when we migrate away from project.json, but the story here is far, far better than it used to be.