add .desktop and ico installation

CMakeLists.txt

@@ -1415,6 +1415,10 @@ if(NOT DEV)
   install(TARGETS ${TARGET_CLIENT} DESTINATION bin COMPONENT client)
   install(TARGETS ${TARGET_SERVER} DESTINATION bin COMPONENT server)
   install(TARGETS ${TARGETS_TOOLS} DESTINATION lib/ddnet COMPONENT tools)
+  install(FILES other/ddnet.desktop DESTINATION share/applications COMPONENT client)
+  foreach(SIZE 16 32 48 128 256 512)
+    install(FILES other/icons/DDNet_${SIZE}x${SIZE}x32.png DESTINATION share/icons/hicolor/${SIZE}x${SIZE}/apps RENAME ddnet.png COMPONENT client)
+  endforeach()
 endif()
 
 if(DEV)

other/ddnet.desktop

@@ -0,0 +1,11 @@
+[Desktop Entry]
+Type=Application
+Name=DDNet
+GenericName=Platform Game
+Exec=DDNet %u
+Icon=ddnet
+Terminal=false
+Keywords=game;multiplayer;
+Categories=Game;ArcadeGame;
+MimeType=x-scheme-handler/ddnet;
+Comment=Launch DDNet