* updates both gltf_auto_export & bevy_gltf_blueprints to avoid duplicating common materials across blueprints
* feat(tools/gltf_auto_export): added materials library export !
* export all materials in use by blueprints to a separate temporary scene with cubes (for now)
with the materials assigned
* injecting MaterialInfo components to each blueprint above with Material name + library name
* generated gltf is named based on the project/blend file, so multiple blend file projects
can each have their own material libraries
* added preferences & ui & handling to be able to toggle material library exports
* feat(bevy_gltf_blueprints): added support for materials library!
* material injection (toggleable via the plugin configuration)
* added example
* added materials library + texture files + updated assets
* added physics debug toggling
* updated documentation
* closes#63
