Added support for exclusion file and sync disable

ansible/roles/veyon/files/veyonStart

@@ -21,8 +21,7 @@
 # Stop system-wide Veyon daemon
 systemctl stop veyon
 
-# This file is recovered by a daemon from the FUSS Server, if it
-# doesn't exists, will default as below.
+wget -O /var/lib/fuss-client/veyon-excluded-groups http://proxy/veyon/excluded_groups || rm -f /var/lib/fuss-client/veyon-excluded-groups
 if [ -e /var/lib/fuss-client/veyon-excluded-groups ]; then
   EXCLUDED_GROUPS="$(xargs < /var/lib/fuss-client/veyon-excluded-groups)"
 else
@@ -36,7 +35,7 @@ BELONGING_GROUPS=" $(id -nG $USER) "
 
 for group in $EXCLUDED_GROUPS; do
   if echo "$BELONGING_GROUPS" | grep " $group "; then
-    python3 /usr/share/fuss-client/roles/veyon/files/veyon-sync-pc-list || true
+    [ -f /var/lib/fuss-client/no-veyon-sync ] && (python3 /usr/share/fuss-client/roles/veyon/files/veyon-sync-pc-list || true)
     exit 0
   fi
 done