Elevate GDAL tags for metadata and fill value from other_tags?

[maxrjones]

GDAL uses the TIFF tags 42112 and 42113 for its metadata and fill value respectively. Would it be in scope to give these preferential treatment over other tags and provide them with descriptive keys in the IFD?

https://github.com/OSGeo/gdal/blob/ecd914511ba70b4278cc233b97caca1afc9a6e05/frmts/gtiff/gtiff.h#L82-L83

[kylebarron]

Yeah that sounds fine. Would you like to submit a PR?