Tooling Should Exist To Evaluate Assumption of No Unit Test Dependency

[aolszowka]

In the README.md one of the assumptions of this tool is:

In addition no project should "depend" on a Unit Test project which means that its unlikely to be blocking any project.

We should have some tooling to try and test this assumption. My first thought would be to use https://github.com/aolszowka/MsBuildProjectReferenceDependencyGraph to look at the dependencies of a project. However that tool, as currently written, only supports looking at ProjectReferences and makes no account for what type of project is being referenced.

We need something that behaves like MsBuildProjectReferenceDependencyGraph but also goes one further in attempting to determine if any of the N-Order Dependencies also reference the NUnit.MSBuild package which would indicate a place where this assumption is broken.