FORGE-2159: Created Dockerfile for JBoss Forge

I'm usnure if this is the best way to install. In general using `curl` and `sh` is a bad combo, especially when you do not use https.

I would say a better idea is to do all the steps that need to be done and add a verion environment variable, so people using this image would immediately know what version it is. It would be easier to maintain the image afterwards too (versioning/tags).

    ENV FORGE_VERSION 2.12.2.Final

This env variable could be used in the Dockerfile too (in urls for example).