Add Better Docs/Samples for Animations component

We should have the following for the Animations package:

```[tasklist]
### Tasks
- [ ] Port existing AnimationSet/ImplicitAnimationSet/AnimationBuilder/Connected/ItemsReorderAnimations docs
- [ ] Better introductory guidance on getting started with Animations in general (central 'Animations' page) - how are these things connected, what types of animations (implicit, explicit, connected, etc...)
- [ ] Ensure there's some basic samples on simple animation sets (Explicit) - no extra frills
- [ ] Bring over existing Connected Animations sample
- [ ] Bring over existing ItemsReorderAnimation sample
- [ ] Bring over Scale animation sample
```

Begin by reviewing the Animations package and any existing AnimationSet, ImplicitAnimationSet, AnimationBuilder, Connected, and ItemsReorderAnimations documentation and samples. Organize a central introduction, port the listed samples, and confirm that every task in the checklist is covered.

Scritto dal modello di indicizzazione a partire dal testo della issue.