Qt/windows: use Qt's high dpi scaling

[Megamouse]

This should work as before now, even on window's high dpi settings.
The main reason for this PR was to use Qt's frontend highdpi stuff instead of using SetProcessDPIAware.
Also fixes a crash on Vulkan when resizing the window to a small height (by setting a min height on Qt side XD).

There is a bug still present in the gs-frame that causes a swapchain error. The max is 1 less than the calculated size on eg. pixelratios of 2

E {rsx::thread} RSX: Swapchain: Swapchain creation failed because dimensions cannot fit. Max = 993, 604, Requested = 994, 604

[Megamouse]

Removed the backend hack.

I changed the code so that APPLE uses AA_EnableHighDpiScaling and therefore devicePixelRatio as well.
I have no idea if this works in any way for MacOs.

The rounding error (width/height mismatch) still persists.

[MSuih]

The latest version seems to fix an issue I've been having for a month where fullscreen is always downsampled to 720p, even though I have windows set to 1080p and resolution scaling at 4k. I'm not 100% confident on this though as the issue seems to come and go with different builds.

Edit: I'm not using dpi scaling or anything like that though, so it might be unrelated. Also I'm using the dll's from 5.11.2, which might explain why I have issues.

[MSuih]

Disregard my previous post I guess, I compiled my own version and it's not working but the one I downloaded from appveyor is.

[Megamouse]

you are probably on a different Qt version or used different dlls

[vietnam13231]

P5: E {RSX [0x0000000]} RSX: Swapchain: Swapchain creation failed because dimensions cannot fit. Max = 1280, 710, Requested = 1280, 711
Current master.

[Zangetsu38]

@vietnam13231 normal, no idea who have said that, but this issue is random, and absolutely don't depending this commit, no relate, this commit only said, "Read dpi value on this system" that all