Refactoring

[tom-englert]

This refactoring was needed to make tests run out of the box everywhere, including CI builds:

• Directory.Build.props added to store common properties
• using C# 10.0 with
  • nullable reference types enabled
  • implicit usings enabled
  • file scoped namespaces
• migrate tests to use DotNet.Testcontainers, so they run everywhere out of the box (only local Docker installation is required)
• added more tests to verify different configurations
• enabled CI-Build via GitHub actions

This is the basis to add more tests to verify the correct behavior of #26

[pada57]

Perhaps easier if I had you as collaborator on project @tom-englert ?

[tom-englert]

Yes, that would be great 😊