[User Interface] Implement UI scaling factor

[SimplyLiz]

Add a scaling factor (1x, 1,5x, 2x, ...) for the UI to support different resolutions.

This scaling factor should be configurable in an ui dialog in settings. The intension behind this is, so user could double / half the size of ui elements, in case someone wants a bigger / smaller ui.

This should be independent from the ui scale that is applied when resizing the game window

[SimplyLiz]

I think this is not important and can be added after v0.3 - UI update

[dalerank]