If provided lighttpd will bind to ServerIPv6 in host mode

[jnss95]

Description

Bugfix of Issues #163 and #239

Motivation and Context

Since I am already running a nginx instance on Port 80 on my machine, I wanted to bind pihole onto a different pair of IP addresses.
This worked fine for IPv4 using the ServerIP environment variable, but failed for IPv6 because lighttpd still tried to bind to [::].

How Has This Been Tested?

Tested on Ubuntu Server 18.40 running Docker 19.03.5 on an AMD64 host system.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[diginc]

If you pull in the latest code from dev branch it should resolve the CI test failures (and switch from travis to Circle CI)

[jnss95]

If you pull in the latest code from dev branch it should resolve the CI test failures (and switch from travis to Circle CI)

Done

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[github-actions]

Existing merge conflicts have not been addressed. This PR is considered abandoned.

[pralor-bot]

This pull request has been mentioned on Pi-hole Userspace. There might be relevant details there:

https://discourse.pi-hole.net/t/support-changing-admin-bind-address-to-something-else-than-ftlconf-local-ipv4/60632/21

[PromoFaux]

@Xeranor - sorry this kind of fell by the wayside - would you like to bring it up to date with the latest changes?