Feature request: Read xmp:rating from .xmp sidecar file

[frspp]

Feature request:

.xmp sidecar is made for each raw image by for example Adobe Bridge. Read xmp:Rating, possibe values 0-5, and show it in browser as rank.

<x:xmpmeta xmlns:x="adobe:ns:meta/" x:xmptk="Adobe XMP Core 5.6-c140 79.160451, 2017/05/06-01:08:21        ">
 <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
  <rdf:Description rdf:about=""
    xmlns:tiff="http://ns.adobe.com/tiff/1.0/"
    xmlns:exif="http://ns.adobe.com/exif/1.0/"
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:aux="http://ns.adobe.com/exif/1.0/aux/"
    xmlns:exifEX="http://cipa.jp/exif/1.0/"
    xmlns:xmp="http://ns.adobe.com/xap/1.0/"
    xmlns:photoshop="http://ns.adobe.com/photoshop/1.0/"
    xmlns:xmpMM="http://ns.adobe.com/xap/1.0/mm/"
    xmlns:stEvt="http://ns.adobe.com/xap/1.0/sType/ResourceEvent#"
    xmlns:crd="http://ns.adobe.com/camera-raw-defaults/1.0/"
    xmlns:crs="http://ns.adobe.com/camera-raw-settings/1.0/"
   tiff:Make="Canon"
   tiff:Model="Canon EOS 5D Mark II"
   xmp:Rating="5"

[Thanatomanic]

Currently only embedded XMP data is read from files. There has been work in the past on implementing xmp-sidecar read/write, but it was never finished. https://github.com/Beep6581/RawTherapee/issues/463

I guess that after we migrate to use exiv2 we can start thinking about this issue again.