Repository: opencv
Issue: G-API: Move OneVPL arguments parser to generic place
Labels: category: g-api / gapi

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##### System information (version)
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- OpenCV => 4.2
- Operating System / Platform => Windows 64 Bit
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- OpenCV => 4.6
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- Compiler => ALL

##### Detailed description
Move `cv::gapi::wip::onevpl::CfgParam create_from_string(const std::string &line);` from [there](https://github.com/opencv/opencv/blob/4.x/modules/gapi/samples/onevpl_infer_single_roi.cpp#L276) to more generic place in `gapi` module in order to make it reusable for all application that are using `onevpl` feature.

##### Steps to reproduce

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