Add support for IPv6

[jovandeginste]

I'm not sure if there are other missing parts, but so far it works for us with the changes in this PR.

[puppetlabs-jenkins]

Can one of the admins verify this patch?

[jovandeginste]

Apologies for the force-pushes - I realized I also changed "old" (changelog) documentation, which is probably not to be touched.

[stelcodes]

Hey @jovandeginste, thanks for this PR! The PuppetDB team is a bit overwhelmed with backlog at the moment, but we will discuss these changes as soon as we can.

[jcpunk]

Any news on this? I'd love to have IPv6 working with the puppetdb container.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}