Enhance security filtering

[christianlupus]

The security-related issue 0.11.5 as fixed in #2898 was a hot-fix to close the major problem. However, there should be additional measures for the admin present to fine-tune the filtering.

There should be an admin configuration present that allows for defining whitelists and blacklists for protocols, hosts (as RegEx), and allowed IPs. Possible option for port restriction and authenticated access as well.