Account for display scaling factor when determining screen resolution

[BinToss]

This is currently being implemented on top of branch develop in new class HXE.Common.DpiUtilies. This class is copied from StackOverflow with little edits and is currently Windows-only. However, it has support for Windows 7 (SP1) and up, but recommends using Win10+ functions because they have better support for per-monitor DPI settings.

If COM marshalling is undesired, the class can be later refactored to utilize CsWin32.

Steal from https://stackoverflow.com/a/54912192

[BinToss]

Work was started in the Avalonia port, but the Avalonia-based solution and the platform-specific fallbacks need testing.