[Exiv2Extractor] Improve extraction of properties and extend tests
Webp was completely untested, as it lacked a test file.
Properties from the Xmp field family were ignored, notably some which have no equivalent in the Exif family.
Webp was completely untested, as it lacked a test file.
Properties from the Xmp field family were ignored, notably some which have no equivalent in the Exif family.