add Collider::from_bevy_mesh_handle as async-asset-loading-compatible alternative to Collider::from_bevy_mesh

[grindhold]

I would love a method that could handle bevy's asynchronous asset loading. Currently a game developer must manually load the assets, make sure they're fully loaded, then instantiate the collider from the mesh and insert it into the world. It would be really awesome if bevy_rapier3d could handle this by itself.

[DiSaber]

I believe this is already handled by AsyncCollider and AsyncSceneCollider. You just have to attach one of these components and it'll be replaced by a collider when the mesh is loaded.