Feature/organize the structure

[Fixstars-momoko]

1. change the structure from

header_library
    gendc_separator
        ContainerHeader.h
        ComponentHeader.h
        PartHeader.h
        Descriptor.h
        tools.h

to

header_library
    gendc_common.h
    gendc_separator
        ContainerHeader.h
        ComponentHeader.h
        PartHeader.h
        Descriptor.h
    genicam
        pfnc_mapping.h
        sfnc_values.h

and API is now available by including gendc_common.h instead of ContainerHeader.h, tools.h, and pfnc_converter.h,

2. Separate const values

All values were in gendc_separator/Descriptor.h, and now pfnc and sfnc information are now in genicam/pfnc_mapping.h and genicam/sfnc_values.h respectively and all header files under gendc_separator do not require these values. Also, added namespace to set the scope for them.

3. Other

• generate_converter is the script to generate mapping header file
• check_pixel_format_update.py is to detect online official document update run by github actions.