Build a docker container with the docker-tools

This is purely for testing, as running docker inside docker
requires further shenanigans, but at least it'll catch if we
ever break this role.

docker/build/docker-tools/Dockerfile

+# To build this Dockerfile:
+#
+# From the root of configuration:
+#
+# docker build -f docker/build/docker-tools/Dockerfile .
+#
+# This allows the dockerfile to update /edx/app/edx_ansible/edx_ansible
+# with the currently checked-out configuration repo.
+
+FROM edxops/xenial-common:latest
+MAINTAINER edxops
+
+ENV PROGRAMS_VERSION=master
+ENV REPO_OWNER=edx
+
+ADD . /edx/app/edx_ansible/edx_ansible
+
+WORKDIR /edx/app/edx_ansible/edx_ansible/docker/plays
+
+COPY docker/build/docker-tools/ansible_overrides.yml /
+RUN sudo /edx/app/edx_ansible/venvs/edx_ansible/bin/ansible-playbook docker-tools.yml \
+    -c local -i '127.0.0.1,' \
+    -t 'install'

docker/build/docker-tools/ansible_overrides.yml

+---
+DOCKER_TLD: "edx"

docker/plays/docker-tools.yml

+- name: build a VM with docker-tools
+  hosts: all
+  sudo: True
+  gather_facts: True
+  roles:
+    - docker
+    - docker-tools

util/parsefiles_config.yml

@@ -24,3 +24,4 @@ weights:
   - programs: 4
   - mysql: 2
   - elasticsearch: 7
+  - docker-tools: 3