Add more Win32 DPI calls

[Lakritzator]

Especially a more convenient way to call:

• https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getsystemmetricsfordpi
• https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-systemparametersinfofordpi