Implement Zero-Configuration Resolution Scaling (#1365)

* Initial implementation of Render Target Scaling

Works with most games I have. No GUI option right now, it is hardcoded.

Missing handling for texelFetch operation.

* Realtime Configuration, refactoring.

* texelFetch scaling on fragment shader (WIP)

* Improve Shader-Side changes.

* Fix potential crash when no color/depth bound

* Workaround random uses of textures in compute.

This was blacklisting textures in a few games despite causing no bugs. Will eventually add full support so this doesn't break anything.

* Fix scales oscillating when changing between non-native scales.

* Scaled textures on compute, cleanup, lazier uniform update.

* Cleanup.

* Fix stupidity

* Address Thog Feedback.

* Cover most of GDK's feedback (two comments remain)

* Fix bad rename

* Move IsDepthStencil to FormatExtensions, add docs.

* Fix default config, square texture detection.

* Three final fixes:

- Nearest copy when texture is integer format.
- Texture2D -> Texture3D copy correctly blacklists the texture before trying an unscaled copy (caused driver error)
- Discount small textures.

* Remove scale threshold.

Not needed right now - we'll see if we run into problems.

* All CPU modification blacklists scale.

* Fix comment.

Ryujinx.Graphics.Shader/Translation/FeatureFlags.cs

@@ -0,0 +1,18 @@
+using System;
+
+namespace Ryujinx.Graphics.Shader.Translation
+{
+    /// <summary>
+    /// Features used by the shader that are important for the code generator to know in advance.
+    /// These typically change the declarations in the shader header.
+    /// </summary>
+    [Flags]
+    public enum FeatureFlags
+    {
+        None = 0,
+
+        // Affected by resolution scaling.
+        FragCoordXY     = 1 << 1,
+        IntegerSampling = 1 << 0
+    }
+}