add check for unsupported environmental variables

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

Containers/mastercontainer/start.sh

@@ -253,6 +253,17 @@ if [ "$?" = 6 ]; then
     exit 1
 fi
 
+# Check if unsupported env are set (but dont exit as it would break many instances)
+if [ -n "$APACHE_DISABLE_REWRITE_IP" ]; then
+    print_red "The environmental variable APACHE_DISABLE_REWRITE_IP has been set which is not supported by AIO. Please remove it!"
+fi
+if [ -n "$NEXTCLOUD_TRUSTED_DOMAINS" ]; then
+    print_red "The environmental variable NEXTCLOUD_TRUSTED_DOMAINS has been set which is not supported by AIO. Please remove it!"
+fi
+if [ -n "$TRUSTED_PROXIES" ]; then
+    print_red "The environmental variable TRUSTED_PROXIES has been set which is not supported by AIO. Please remove it!"
+fi
+
 # Add important folders
 mkdir -p /mnt/docker-aio-config/data/
 mkdir -p /mnt/docker-aio-config/session/