Use of XMP metadata in Khoj Image Search is broken. Disable by default

- CLIP Image score and XMP metadata score are not combining well.
  When combined they give non sensical results. Enable only once
  figure how best to combine the two.

- Show scores with higher precision for image search
  - Image search scores seem to be mostly be between 0.2 - 0.3 for some reason
  - Higher precision scores make it easier to understand the quality
    of returned results perceived by the model itself

config/khoj_sample.yml

@@ -22,7 +22,7 @@ content-type:
     input-filter:      # /path/to/images/*.jpg  REQUIRED IF input-directories IS NOT SET
     embeddings-file: "~/.khoj/content/image/image_embeddings.pt"
     batch-size: 50
-    use-xmp-metadata: true
+    use-xmp-metadata: false
 
   music:
     input-files:  # ["/path/to/music-file.org"] REQUIRED IF input-filter IS NOT SET OR