Added xml appdata to linux distribution

Fix #4406

Author: cmaglie

build/build.xml

@@ -572,6 +572,7 @@
 
     <copy tofile="linux/work/lib/arduino-arduinoide.xml" file="linux/dist/mime.xml" />
     <copy todir="linux/work/lib" file="linux/dist/desktop.template" />
+    <copy todir="linux/work/lib" file="linux/dist/appdata.xml" />
 
     <copy todir="linux/work" file="linux/dist/arduino" />
     <copy todir="linux/work" file="linux/dist/install.sh" />