This change updates our docker build and examples in several ways:

Update Dockerfile to move from deprecated ENV key value to

ENV key=value
Update Dockerfile to switch from deprecated MAINTAINER to

LABEL org.opencontainers.image.authors
Fix the docker build.py script to look for the correctly normalized

  wheel package name.
Change example docker-compose files to list "reviewboard.example.com"

  instead of "localhost", and add a section for setting the custom

  domain name as an alias for nginx (in the case where people have used

  /etc/hosts to create a fake domain).

Built the docker image using new RB8/Power Pack 6 packages.
Stood up an RB8 docker-compose.
Went through the activation flow for an RB plus license.
Configured the broker for document review.
Uploaded a .docx and saw it successfully convert.