MaterialSkin 2 for .NET WinForms 10+, AOT publishing compatible

Theming .NET WinForms to Google's Material Design principles.

This project was initially developed here from multiple forks https://github.com/leocb/MaterialSkin.

From there, I have done the following:

• ported the project to .NET Core 10+

• removed the MaterialSkinCore project, as it's not needed anymore

• removed .NET Framework projects (use previous forks if you need them)

• added AOT publishing support (changed interop code, remove some dependencies on resx, etc.)

• cleaned up C# code so it's more aligned with "modern" C#

  • consolidate using usage in csproj
  • enable <nullable>
  • enforce usual naming convention
  • enforce 1 public type => 1 file
  • removed all warnings
  • etc.

Note: The project is not Hi-DPI aware, as this require some amount of work since many values are currently hardcoded.