CMake: Installing 128x128 png to the right place and rename it

According to Freedesktop spec the icon should be placed in the fallback theme and use the id of the application.

Signed-off-by: Thomas Karl Pietrowski <thopiekar@gmail.com>

CMakeLists.txt

@@ -203,7 +203,9 @@ install(
 )
 install(
     FILES ${CMAKE_SOURCE_DIR}/resources/icons/qgroundcontrol.png
-    DESTINATION ${CMAKE_INSTALL_DATADIR}/icons/
+    DESTINATION ${CMAKE_INSTALL_DATADIR}/icons/hicolor/128x128/apps/
+    RENAME org.mavlink.qgroundcontrol.png
+)
 )
 
 if(BUILD_TESTING)

deploy/org.mavlink.qgroundcontrol.desktop

@@ -3,7 +3,7 @@ Type=Application
 Name=QGroundControl
 GenericName=Ground Control Station
 Comment=UAS ground control station
-Icon=qgroundcontrol
+Icon=org.mavlink.qgroundcontrol
 Exec=QGroundControl
 Terminal=false
 Categories=Utility;