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/CMakeLists.txt

@@ -19,9 +19,15 @@ macro(kimageformats_read_tests)
     endif()
 
     foreach(_testname ${KIF_RT_UNPARSED_ARGUMENTS})
+        string(REGEX MATCH "-skipoptional" _is_skip_optional "${_testname}")
+        unset(skip_optional_arg)
+        if (_is_skip_optional)
+            set(skip_optional_arg "--skip-optional-tests")
+            string(REGEX REPLACE "-skipoptional$" "" _testname "${_testname}")
+        endif()
         add_test(
             NAME kimageformats-read-${_testname}
-            COMMAND readtest ${_fuzzarg} ${_testname}
+            COMMAND readtest ${skip_optional_arg} ${_fuzzarg} ${_testname}
         )
     endforeach(_testname)
 endmacro()
@@ -132,9 +138,15 @@ if (OpenJPEG_FOUND)
 endif()
 
 if (LibJXL_FOUND AND LibJXLThreads_FOUND)
-    kimageformats_read_tests(
-        jxl
-    )
+    if(LibJXL_VERSION VERSION_GREATER_EQUAL "0.11.0")
+        kimageformats_read_tests(
+            jxl
+        )
+    else()
+        kimageformats_read_tests(
+            jxl-skipoptional
+        )
+    endif()
     kimageformats_write_tests(
         jxl-nodatacheck-lossless
     )