documentation: Setup directories with correct permissions
In order for suricata-update to run without a sudo or as a root, the following permissions are required:
- Directory /etc/suricata: read access
- Directory /var/lib/suricata/rules: read/write access
- Directory /var/lib/suricata/update: read/write access
- create a suricata group.
- setup the above directories with the correct permissions for the suricata group.
- add users to the suricata group.