lazy import for task manager (#844)
* lazy
* lazy onnx
* lazy tflite
* doc build test
* test done
* task manager lazy mapping
* fix tflite
* test revert tflite
* test doc fix
* test doc fix
* fix doc build docker
* fix style
* revert type checking
* put back lazy tflite import
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Co-authored-by: JingyaHuang <jingya@huggingface.co>
