Request for Java7

I would like to request support for java7 containers; some of the forge servers and plugins did not support java 8+
It can be a one-time spin-off of the java8 container (FROM openjdk:7u211-jre-alpine). I have a PR open: on Custom Server Packs; which would be great to make it onto a java7 branch.

In the future, I would not mind if it was not supported anymore, because these servers probably will not change the plugins. Plus the feature base you have currently for setting up containers is impressive and works very well for older servers;

Start by reviewing the existing Java 8 container and the mentioned Custom Server Packs PR, then check how container variants are organized. Done means a Java 7 container variant based on openjdk:7u211-jre-alpine is available for older Forge servers and plugins, with the relevant setup checks passing.

Written by the indexing model from the issue text.