Add new animation-mixer and loop-animation components.

package.json

src/assets/avatars/BotDefault_Avatar.glb

src/assets/avatars/BotDefault_Avatar_Unlit.glb

src/assets/avatars/Bot_SingleSkin_Rigged.glb

src/components/animated-robot-hands.js

src/components/animation-mixer.js

src/components/loop-animation.js

src/gltf-component-mappings.js

src/room.html

src/room.js

yarn.lock