Consolidate screen size/density APIs

[hartez]

We currently have two competing APIs for determining display density and screen size - one from Essentials (with the DisplayInfo struct) and another in WindowHandler (using GetDisplayDensity()). Which is confusing, especially since they have differing opinions on what the density should be when a Window/Screen is not available.

We need to consolidate these APIs to reduce confusion and increase consistency.

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.