add check for timezone

Signed-off-by: Simon L <szaimen@e.mail.de>

Containers/mastercontainer/start.sh

@@ -253,6 +253,18 @@ if [ "$?" = 6 ]; then
     exit 1
 fi
 
+# Check that no changes have been made to timezone settings since AIO only supports running in UTC timezone
+if [ -n "$TZ" ]; then
+    print_red "The environmental variable TZ has been set which is not supported by AIO since it only supports running in the default UTC timezone!"
+    exit 1
+elif mountpoint -q /etc/localtime; then
+    print_red "/etc/localtime has been mounted into the container which is not allowed because AIO only supports running in the default UTC timezone!"
+    exit 1
+elif mountpoint -q /etc/timezone; then
+    print_red "/etc/timezone has been mounted into the container which is not allowed because AIO only supports running in the default UTC timezone!"
+    exit 1
+fi
+
 # Add important folders
 mkdir -p /mnt/docker-aio-config/data/
 mkdir -p /mnt/docker-aio-config/session/