Encapsulated gradient transform logic into separate class (#6586)

* First version of GradientTransform class.
The gradient transform logic is getting encapsulated into a class so that it can be cached and used by components in a much more optimal way than making ebus calls to the GradientTransform component on every transformed point.

Signed-off-by: Mike Balfour <82224783+mbalfour-amzn@users.noreply.github.com>

* Moved GradientTransform into its own source files.

Signed-off-by: Mike Balfour <82224783+mbalfour-amzn@users.noreply.github.com>

* Clean up and simplify GradientTransform logic.
Added extensive commenting and split TransformPositionToUVW into a separate method for normalizing (TransformPositionToUVWNormalized) so that there doesn't need to be any conditional logic.  There's no runtime variance as to which one needs to be called from a given call site.

Signed-off-by: Mike Balfour <82224783+mbalfour-amzn@users.noreply.github.com>

* Added unit tests for GradientTransform.

Signed-off-by: Mike Balfour <82224783+mbalfour-amzn@users.noreply.github.com>

* Add comparison operators to GradientTransform so we can easily tell when it has changed.

Signed-off-by: Mike Balfour <82224783+mbalfour-amzn@users.noreply.github.com>

* Updated comments to be more Doxygen-friendly.

Signed-off-by: Mike Balfour <82224783+mbalfour-amzn@users.noreply.github.com>

Gems/GradientSignal/Code/Source/Components/ImageGradientComponent.cpp

@@ -194,9 +194,8 @@ namespace GradientSignal
         AZ::Vector3 uvw = sampleParams.m_position;
 
         bool wasPointRejected = false;
-        const bool shouldNormalizeOutput = true;
         GradientTransformRequestBus::Event(
-            GetEntityId(), &GradientTransformRequestBus::Events::TransformPositionToUVW, sampleParams.m_position, uvw, shouldNormalizeOutput, wasPointRejected);
+            GetEntityId(), &GradientTransformRequestBus::Events::TransformPositionToUVWNormalized, sampleParams.m_position, uvw, wasPointRejected);
 
         if (!wasPointRejected)
         {