* closes#80
* preliminary work for further asset management from the Blender side without needing additional dependencies & boilerplate on the Bevy side
* feat(auto_export):
* now injecting list/tree of sub blueprints to main scenes/levels & blueprints
* made blueprints/asset list conditional on NOT legacy mode
* feat(gltf_blueprints):
* basics of dynamic loading of sub_blueprints
* added same kind of logic to the loading of material files
* also made a more generic variant of the BlueprintAssetLoadTracker
* added gltf file path for more informative error in case a gltf is missing
* refactor():
* made the various gltf assets loaded by bevy_asset_loader optional (to handle the case where they are not present)
* updated all examples accordingly
* chore(crates): fixed links, slight tweaks, bumped versions
* chore(crates): updated crates to Bevy 0.13
* updated deps
* updated / changed code where relevant
* updated README files
* bumped version numbers for upcoming release
* updated rust-toolchain
* updated assets where relevant
* closes#132
* feat(bevy_gltf_components):
* added GltfProcessed flag component to improve performance of iteration over added<gltfExtras>
* closes#144
* light & shadow processing is now integrated, to match lights coming from Blender: you can now control whether
lights cast shadows, the cascade resolution , background color etc from Blender
* closes#155
* feat(bevy_registry_export): added boilerplate to make registry path relative to assets folder
* closes#137
* feat(tools): added boilerplate for internal tools
* clean zip file generator for blender add-on releases
* example gltf file generator
* feat(lighting): added components, exporter support & testing for blender-configurable shadows
* added BlenderLightShadows component to bevy_gltf_components
* added writing shadow information to gltf_auto_export
* updated tests
* closes#157
Co-authored-by: Jan Hohenheim <jan@hohenheim.ch>
