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)

CMakeLists.txt

@@ -8,7 +8,7 @@ set_package_properties(ECM PROPERTIES TYPE REQUIRED DESCRIPTION "Extra CMake Mod
 feature_summary(WHAT REQUIRED_PACKAGES_NOT_FOUND FATAL_ON_MISSING_REQUIRED_PACKAGES)
 
 
-set(CMAKE_MODULE_PATH ${ECM_MODULE_PATH})
+set(CMAKE_MODULE_PATH ${KImageFormats_SOURCE_DIR}/cmake/find-modules ${ECM_MODULE_PATH})
 
 include(KDEInstallDirs)
 include(KDEFrameworkCompilerSettings NO_POLICY_SCOPE)
@@ -70,6 +70,13 @@ if(KIMAGEFORMATS_JXL)
 endif()
 add_feature_info(LibJXL LibJXL_FOUND "required for the QImage plugin for JPEG XL images")
 
+# note: module FindLibRaw missing from https://invent.kde.org/frameworks/extra-cmake-modules
+find_package(LibRaw 0.20.2)
+set_package_properties(LibRaw PROPERTIES
+    TYPE OPTIONAL
+    PURPOSE "Required for the QImage plugin for RAW images"
+)
+
 ecm_set_disabled_deprecation_versions(
     QT 5.15.2
     KF 5.95