new backup structure

By default, the script will leave the folders "data", "config", "apps" and "themes" within your nextcloud path.
That's usefull for example if you have mass data and copying data to another folder would take too long..
You can enable a file backup (copy data files to another folder) by starting the script with "-b" option:
./ncupdate.sh -b or ./ncupdate.sh --backup