Add area sampling scaler to allow for super-sampled anti-aliasing. (#7304)

* Add area sampling scaler to allow for super-sampled anti-aliasing.

* Area scaling filter doesn't have a scaling level.

* Add further clarification to the tooltip on how to achieve supersampling.

* ShaderHelper: Merge the two CompileProgram functions.

* Convert tabs to spaces in area scaling shaders

* Fixup Vulkan and OpenGL project files.

* AreaScaling: Replace texture() by texelFetch() and use integer vectors.

No functional difference, but it cleans up the code a bit.

* AreaScaling: Delete unused sharpening level member.

Also rename _scale to _sharpeningLevel for clarity and consistency.

* AreaScaling: Delete unused scaleX/scaleY uniforms.

* AreaScaling: Force the alpha to 1 when storing the pixel.

* AreaScaling: Remove left-over sharpening buffer.

src/Ryujinx.Graphics.GAL/UpscaleType.cs

@@ -5,5 +5,6 @@ namespace Ryujinx.Graphics.GAL
         Bilinear,
         Nearest,
         Fsr,
+        Area,
     }
 }