[Serving] Modify OCR related model functions to support Serving

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PR types(PR类型)

[Serving] Modify OCR related model functions to support Serving

Describe

1.Modify OCR related model functions to support Serving 2.Add new pybind interface for preprocess and postprocess

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:white_check_mark: yunyaoXYY
:white_check_mark: jiangjiajun
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:x: root

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