JXL: Resolution and metadata support via EXIF

- Added a class to read and write minimal exif metadata.
- JXL plugin uses EXIF metadata to load/save the resolution of the image (like GIMP).
- JXL plugin uses EXIF metadata to set/store text metadata and date/time.
- Enable info display in Dolphin (JXL File -> Properties -> Details on a JXL file, see image below).
- Enabled read test to check also image metadata and resolution.

![_52C044E4-1BA9-4D84-AC0A-B834CDAF72D8_](/uploads/f1649c2b506bf61a5f5488da0d4a4534/_52C044E4-1BA9-4D84-AC0A-B834CDAF72D8_.png){width=401 height=357}

autotests/templateimage.h

@@ -8,6 +8,7 @@
 #define TEMPLATEIMAGE_H
 
 #include <QFileInfo>
+#include <QImage>
 
 /*!
  * \brief The TemplateImage class
@@ -60,6 +61,15 @@ public:
      */
     QFileInfo compareImage(TestFlags &flags, QString& comment) const;
 
+    /*!
+     * \brief checkOptionaInfo
+     * Verify the optional information (resolution, metadata, etc.) of the image with that in the template if present.
+     * \param image The image to check optional information on.
+     * \param error The error message when returns false.
+     * \return True on success, otherwise false.
+     */
+    bool checkOptionaInfo(const QImage& image, QString& error) const;
+
     /*!
      * \brief suffixes
      * \return The list of suffixes considered templates.