Make it easier to handle extended transition configuration

[Clpsplug]

Is your feature request related to a problem? Please describe.

The SceneTransitionConfiguration can be extended to add game-specific transition-time configurations.
The amount of code needed to extend the class is relatively large.

• The extended class itself
  • A static method that downcasts the original class into the extended class
  • Builder methods
• Extension function for the original class that calls the static upcasting method
  (which allows the user to integrate the upcast into builder method chaining.)

Describe the solution you'd like

Not yet discussed; I want to add something that can reduce the amount of code on the user side.

Describe alternatives you've considered

N/A

Additional context

N/A