drag-and-drop demo

[soelen]

A rough implementation, here are some thoughts:

• I tried to follow your idea with the vite setup and created a second page for the drag and drop demo.
• I tried to make the sidebar reusable throughout demos by using web components.
• I created 3 example files which users can try out if they don't have a gltf file on hand. Furthermore I also provided blend files; I remember when I started with this package I was not sure how the export should actually look like, a blender file would have probably helped me a lot.
• I focused more on the drag and drop demo than making the demos simplier. Please let me know if something from this pr is reusable, if changes needs to be done or this pr needs to be purged. I am super flexible :)

[soelen]

So I thought about this pr and I think these steps would move this pr in the right direction:

• Make scene setup, mouse interactions and raf tick reusable (less boilerplate code),
• Host blend and glb example files somewhere else (blendswap?, sketchfab?)
• In addition: Add mobile support for sidebar and interaction events if possible

What do you think?

[soelen]

As stated in the commit message: Demo can be seen now on mobile view as well since sidebar got some mobile capabilities. In created and placed a drag and drop area on top of the empty webgl canvas; it sort of looked empty when no gltf file has been selected.

As usual: Please let me know if changes need to be done / if I went to far etc.

[soelen]

IMHO: I kind of like the teleport demo. Showing that three-pathfnding has teleportation capabilities is a good idea I think. On a subjective note I also adore the model :)