refactor: split Model and AtomicModel #6324

Job	Run time
Build source distribution	13s
determine-arm64-runner	1s
Build wheels for cp311-manylinux_x86_64	6m 35s
Build wheels for cp311-manylinux_x86_64	5m 46s
Build wheels for cp311-macosx_x86_64	7m 0s
Build wheels for cp311-macosx_arm64	3m 17s
Build wheels for cp311-win_amd64	6m 58s
Build wheels for cp310-manylinux_aarch64	5m 34s
build_docker (12)	7m 49s
build_docker (_cu11, 11)	4m 0s
upload_pypi	0s
build_pypi_index	19s
deploy_pypi_index	0s
Pass testing build wheels	2s
	47m 34s

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