Research: Modernization of Qt backends on Windows

Currently Windows backends in Qt which are based on WinRT APIs (not Win32) use raw COM pointer functionality. This approach has several drawbacks such as:

• Unreadable code and thus high maintenance effort
• Inconsistent error handling across modules/backends
• Inconsistent use of best practices and thus bugs

By switching over to c++/winrt for these backends most of these issues could be fixed.

Open questions are:

• Which backends need to be ported?
• What's the effort estimate for the port?
• What's the level of support for c++/winrt in other Windows toolchains?
• Are there toolchains that do support WinRT APIs but do not support c++/winrt? Thus: Would we lose functionality?