NTP server configuration does not highlight selected interfaces

Missing explode of selected interface list prevent logic from working.
Merge pull request #1286 from jean-m-cyr/master
Provide upgrade config code to migrate unbound settings from 2.1 package to 2.2 base. Bump config version to 11.1. It fixes #3880
Make sure unbound user and group is also created during upgrade config
Add a note clarifying the usage of OpenVPN's Auth Digest setting.