Animation: State Blending

[eprikazchikov]

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

For better game experience I'm suggesting to implement animation blending during state transition.

Describe the solution you'd like

Animation clips blending functionality must be implemented in AnimationController class. Doing transition it will blend animations between Source State and Destination State. The blending options must be described in State Transitions.

Describe alternatives you've considered

N/A

Additional context

N/A