Convert BPMemory to BitField and enum class

Additional changes:
- For TevStageCombiner's ColorCombiner and AlphaCombiner, op/comparison and scale/compare_mode have been split as there are different meanings and enums if bias is set to compare.  (Shift has also been renamed to scale)
- In TexMode0, min_filter has been split into min_mip and min_filter.
- In TexImage1, image_type is now cache_manually_managed.
- The unused bit in GenMode is now exposed.
- LPSize's lineaspect is now named adjust_for_aspect_ratio.

Source/Core/VideoCommon/SamplerCommon.h

@@ -16,13 +16,13 @@ namespace SamplerCommon
 template <class T>
 constexpr bool IsBpTexMode0PointFiltering(const T& tm0)
 {
-  return tm0.min_filter < 4 && !tm0.mag_filter;
+  return tm0.min_filter == FilterMode::Near && tm0.mag_filter == FilterMode::Near;
 }
 
 // Check if the minification filter has mipmap based filtering modes enabled.
 template <class T>
 constexpr bool AreBpTexMode0MipmapsEnabled(const T& tm0)
 {
-  return (tm0.min_filter & 3) != 0;
+  return tm0.mipmap_filter != MipMode::None;
 }
 }  // namespace SamplerCommon