Support auto-conversion between supported formats rather than requiring user to provide all

[dementrock]

e.g. rather than having to provide all of usd/mjcf/urdf for cross platform compatibility, allow user to just supply one, and auto-generate the others

same goes for inserting a mesh from obj/glb/etc files; ideally don't have to generate more boilerplates

[Fisher-Wang]

Thank you Rocky! As a quick note, this was discussed in #37

[Fisher-Wang]

@charlietcheng, could you share your thoughts on the level of effort required to integrate the asset conversion workflow into runtime?

[charlietcheng]

Hi Rocky. This is a very cool feature and thanks for bringing this up. We had some discussion regarding the online conversion of assets. The pain we are currently facing is to set up a standardized workflow for parsing/converting assets in different format. The current asset converter is still having trouble aligning the texture with the mesh correctly (mostly mjcf->urdf). We are actively trying to address the issue and will update the asset conversion part accordingly. This might take a while as we will have to play around with a good amount of existing assets and make sure we have a stable asset converter