Add Tests to Ensure DSC Resource Names are added to DSCResourcesToExport in Manifest

[PlagueHO]

It is a best practice that any DSC resources included in a module are listed in the DSCResourcesToExport field in the Module Manifest. See https://ci.appveyor.com/project/dscbot/gpregistrypolicydsc/builds/27503170#L1204

We should add tests to ensure this is happening.

This will likely break many modules, so opt-in might be something we implement.