Updated the jekyll-asciidoc-docker to support running as a Jenkins slave

[sabre1041]

What does this PR do?

Enable jekyll-asciidoc-docker container to be used as a Jenkins slave for building openshift-playbooks in Jenkins

How should this be manually tested?

1. Navigate to the container folder (docker/jekyll-asciidoc-docker)

2. Build a new image

   docker build -t rhtconsulting/jekyll-asciidoc .

3. Run a new container

   docker run -it --rm -P rhtconsulting/jekyll-asciidoc /usr/sbin/sshd -D

4. Determine the port that has been assigned for SSH

   docker ps | grep rhtconsulting/jekyll-asciidoc`

5. Inspect the result. Look for the value preceded by ->22

   b6489098f923        rhtconsulting/jekyll-asciidoc   "/usr/sbin/sshd -D"   5 minutes ago       Up 5 minutes        0.0.0.0:32770->4000/tcp, 0.0.0.0:32771->22/tcp   goofy_stallman 

In this case, it is port 32771

6.. Attempt to connect to the container via SSH

ssh -p 32771 builder@<DOCKER_HOST>

Is there a relevant Issue open for this?

None

Who would you like to review this?

/cc @etsauer

[sabre1041]

@etsauer Added clarification to message