[handler] Extract translatable strings from ui file

(cherry picked from commit 85b32083)

urlhandler/Messages.sh

 #!/usr/bin/env bash
 
+$EXTRACTRC `find . -name '*.ui' -o -name '*.rc'` >> rc.cpp
 $XGETTEXT `find . -name '*.cpp'` -o $podir/kdeconnect-urlhandler.pot
+rm -f rc.cpp