Reorganize project to create a .netstandard 2.0 library as well as upgrade to .Net 4.8 for anything targeting .Net Framework

[jshergal]

@haf This is just a stub issue, but I think it would be good to update and potentially simplify the whole project. It would be a good first step to move everything into the new .Net SDK project format and then we could discuss what kind of reorganization could be done to clean it up a bit. I would suggest potentially moving the code to use GitHub Actions for building, etc. It is a tall order, but I think step by step it would make the project more maintainable and the build system a bit cleaner.