Overhaul QML/Quick animation framework

The current animation framework has a few short-comings and issues. The most severe being a rather questionable lifetime management (cf RETURN_IF_DELETED).

Other reported issues revolve around more fine-grained control over animations, e.g. being able to accelerate or decelerate a running animation or changing an animations from and to values while it is ongoing. It is also telling that QDS has a mostly unrelated animation system with the timeline animation.

This epic is meant to track various improvements that should be applied to the animation system.