[gentoo-containers] Gentoo LibreSSL Docker image

[Andrey Utkin]

Hi Gentoo Docker Images maintainers,

I have sketched a Docker image of base Gentoo system with LibreSSL instead of
OpenSSL. https://github.com/andrey-utkin/gentoo-libressl-docker

This should come handy in the effort of LibreSSL support across Gentoo,
https://bugs.gentoo.org/561854

The Dockerfile is just a representation of the user howto for migration to
LibreSSL, with minimal deviations.

On which conditions would you agree to include such an image into the list of
official Gentoo images on Dockerhub?