This change:

1. Creates a .netstandard2.0 c# library that supports loading, validation, and conversion of supported yaml schemas into rest compatible json.
2. Refactors a slew of utilities into a utility project that can be used by the powershell library as well as the rest source.
3. Updates some code to be netstandard2.0 compliant.

We standardize on netstandard2.0 to be compatible with both 5.1 and 7.* powershell going forward.