Add docs for new animation types

Our documentation on Qt Quick Animations (found here: https://doc.qt.io/qt-6/qtquick-statesanimations-animations.html) does not mention the Render-Thread Animators (found here: https://doc.qt.io/qt-6/qml-qtquick-animator.html) or the new Timeline Animation (found here: https://doc.qt.io/qt-5/qtquicktimeline-overview.html).

We should probably update the general Animations page to at least reference these, but probably also could use some more clarification on when they are good to use.