Switch to Microsoft.Windows.CsWin32

[virzak]

Consider switching to Microsoft.Windows.CsWin32. The related PR is #84

The main benefit of generated P/Invoke methods is that the project contains less code and instead relies on the generated building block. This will result in:

• Ease of implementing future controls
• Standardized constant, method, and enumeration names, guaranteed to be identical to Win32
• Codesharing across the projects and ease of adoption
• Less error-prone code, since there is no opportunity to get it wrong

Previously recommended approach dotnet/pinvoke is currently recommends Microsoft.Windows.CsWin32 source generators

[virzak]

Hi @augustoproiete, have you had a chance to take a look? I'd like to submit another PR soon related to Async handling of ProgressTask, but I'm not sure I should open two PRs at the same time.