Windows: Updated app icons, deploy Doomsday icon to data/graphics/

ClientWindow was trying to load "doomsday.ico" from a native file but
apparently it wasn't being deployed in the installation.

The app icons now contain sizes 16x16, 32x32, 48x48 and 256x256.

Related to IssueID #1589.
Fixed|Windows|Installer: Path of the app icon file