Refactor global state for built-in pixel shader effects

[Sergio0694]

Description

This PR refactors the internal Foo<T> type used by the built-in pixel shader effects, and switches that to use a Globals abstract class with all shader properties, and derived Globals<T> class implementing all properties for each shader type T. The factory will now pass that instance, and the pixel shader effect will use a GCHandle to resolve Globals instances and invoke members on it. This avoids the need to manually copy all properties from the shader at construction time, from the static constructor. Now they're all lazily initialized instead, as an additional bonus.