Data Sources should support for .NET Standard in addition to Core

[adamfoneil]

Assembly data sources currently must be Netstandard 2.0, which is too restrictive. ModelSync should support .NET6, and support .NET evolution generally.

I believe @usmanasfandiCheetah you are close to having this working already. I think you felt you could have a video demo of this Friday 9/2

[adamfoneil]

@desirablecoder I know you have some work on this as well -- I'm happy to look at multiple solutions