Camera RAW images plugin

Plugin to read RAW camera images based on LibRAW.

- Supersedes MR !86 
- Support to LibRaw 0.20 and 0.21-Beta
- Support to multi-shot images: use imageCount(), jumpToImage() to select the wanted shot
- By default generates 16-bits sRGB images using camera white balance and interpolation AHD
- Should fix CCBUG: 454208: on my Debian with KF5.96 and the pulgin installed, I see the preview of all my RAW files (ARW included) in Dolphin

News compared to V1 (MR !86)

- Fix possible stack overflow due to the huge size of LibRaw class
- Fix image allocation with Qt 6 (make use of QImageIOHandler::allocateImage()) 
- Support to XMP metapacket
- Support to quality option. For e.g. you can focus on quality (q = 10) or speed (q = 1)
- oss-fuzz available [here](https://github.com/mircomir/oss-fuzz/tree/raw_fuzz/projects/kimageformats)

autotests/readtest.cpp

@@ -94,7 +94,6 @@ int main(int argc, char **argv)
     QByteArray format = suffix.toLatin1();
 
     QDir imgdir(QLatin1String(IMAGEDIR "/") + suffix);
-    imgdir.setNameFilters(QStringList(QLatin1String("*.") + suffix));
     imgdir.setFilter(QDir::Files);
 
     int passed = 0;
@@ -113,6 +112,9 @@ int main(int argc, char **argv)
 
     const QFileInfoList lstImgDir = imgdir.entryInfoList();
     for (const QFileInfo &fi : lstImgDir) {
+        if (!fi.suffix().compare("png", Qt::CaseInsensitive)) {
+            continue;
+        }
         int suffixPos = fi.filePath().count() - suffix.count();
         QString inputfile = fi.filePath();
         QString expfile = fi.filePath().replace(suffixPos, suffix.count(), QStringLiteral("png"));