Add an option to configure render scaling

[jellysquid3]

Problem

Since we don't intend to encourage the use of exclusive fullscreen mode (see https://github.com/CaffeineMC/sodium-fabric/issues/2359), the game will often be rendering at the monitor's native resolution. This may be unnecessary, and in some cases, detrimental to performance. For macOS in particular, their displays are very high resolution, and their laptops are often not powerful enough to render any kind of game at native resolution.

Solution

We should implement an option to allow the user to select a lower resolution for rendering, which is then upscaled to the monitor's native resolution. The implementation of render scaling should only affect world rendering, and not the user interface.

Please note, implementing any advanced upscaling technologies (FSR, DLSS, XeSS, etc) is not in scope for this issue. These require motion vectors to function correctly, and generating those is not trivial. It's also not clear to me whether these technologies would make much sense, given the kind of workload that Minecraft is.