Add JPEG 2000 support

JPEG 2000 support using OpenJPEG library.

- Add read/write support to JP2/J2K format for Gray/RGB(A)/CMYK images @8/16-bits
- Read test case images generated by Photoshop

The plugin has the following limitations:
- Resolution is not set (JP2_RES box is marked "For the future" in jp2.h)
- Metadata are not set (as with resolution)

Closes #13

autotests/CMakeLists.txt

@@ -119,6 +119,18 @@ if (LibHeif_FOUND)
     endif()
 endif()
 
+if (OpenJPEG_FOUND)
+    kimageformats_read_tests(
+        jp2
+    )
+    # CMYK writing is incorrect in versions before 2.5.3
+    if ("${OPENJPEG_MAJOR_VERSION}.${OPENJPEG_MINOR_VERSION}.${OPENJPEG_BUILD_VERSION}" VERSION_GREATER_EQUAL "2.5.3")
+        kimageformats_write_tests(
+            jp2-nodatacheck-lossless
+        )
+    endif()
+endif()
+
 if (LibJXL_FOUND AND LibJXLThreads_FOUND)
     kimageformats_read_tests(
         jxl