Add composite animations

[ambrosiogabe]

Often times you need to add a group of animations that together. It's annoying placing all these on separate timeline tracks and then carefully aligning them etc. Maybe it's possible to add an AnimationGroup thing similar to Manim. Where you can add several different animations to this group then you can synchronize them or play them lagged.

The difficult part for this is how should the UI look? Should you be able to double click into an animation group on the timeline and then edit each animation individually in a sub-timeline kind of thing? Or should the animation inspector just show a bunch of animations and allow you to click them and then open a sub-menu?

I like the idea of the sub-timeline opening up, kind of like how code editor open the context of the file you're looking at a function inline. This sounds plausible but will require a lot of effort to add feature support on the timeline for this. Might be worth it though...