* Add craft-crs: Camera Raw crs: settings in XMP, read and written, from PhotoCraft
The format half of PhotoCraft's Camera Raw settings files (crates/io/src/camera_raw_xmp.rs at
abeb16c96): the crs: settings of an XMP packet as written, Camera Raw's number and curve point
text, the crop and its orientation, a writer, and the toolkit marker. Which setting drives
which control stays in the app.
* craft-crs: structures carry their element and are written back
Local corrections and other structured settings were dropped, and an rdf:Seq of descriptions
read as empty strings. A structure now holds its crs: element, a sequence is only plain text
items, descriptions inside a structure are not read as top-level settings, and to_xmp writes
structures back.
* craft-crs: read packets through craft-metadata's XMP reader
One XMP reader for every crate: Settings::parse goes through craft_metadata::parse_xmp and
Settings::from_xmp takes its XmpData. Settings are kept by name (the reader's map has no file
order), structures are craft-metadata's XmpValue and are written back as rdf:parseType
Resource elements and rdf:Seq arrays. toolkit stays a bounded first-start-tag scan, as the
reader does not return x:xmptk.
