Add more information to appdata xml

- Add oars content rating to appdata xml
- Add screenshots to appdata xml
- Add release info

Change-Id: I61bf023814149983f7a64e03f49eb8d998dac85b
Reviewed-by: Youri Westerman <tetracon@gmail.com>
Reviewed-by: Cristian Adam <cristian.adam@qt.io>

share/CMakeLists.txt

@@ -1,11 +1,23 @@
 add_subdirectory(qtcreator)
 
 if (NOT APPLE AND NOT WIN32)
+  set(DATE_ATTRIBUTE)
+  if(SHOW_BUILD_DATE)
+    string(TIMESTAMP timestamp "%Y-%m-%d")
+    set(DATE_ATTRIBUTE " date=\"${timestamp}\"")
+  endif()
+  configure_file(metainfo/org.qt-project.qtcreator.appdata.xml.cmakein metainfo/org.qt-project.qtcreator.appdata.xml)
+
   install(
     DIRECTORY
       applications
-      metainfo
     DESTINATION
       ${CMAKE_INSTALL_DATAROOTDIR}
   )
+  install(
+    FILES
+      ${CMAKE_CURRENT_BINARY_DIR}/metainfo/org.qt-project.qtcreator.appdata.xml
+    DESTINATION
+      ${CMAKE_INSTALL_DATAROOTDIR}/metainfo/
+  )
 endif()