Initial new dpi management support for Shortcut Mapper

[ozone10]

ref #14959

[donho]

@ozone10
By "Initial new dpi management support for Shortcut Mapper" I guess it doesn't do the multi-display support, but it should scale
correctly in the mono screen.

However, I've got this when I scale my current display from 225% to 300% :

[ozone10]

@donho
changing dpi in single screen is same as dragging to second screen.
This PR only handle initial opening of shorcut mapper, mainly font handling.
To fully support DPI, WM_DPICHANGED, WM_GETDPISCALEDSIZE need to be handled and WM_SIZE rewritten.