Refactor roles to support new variable schema

Add common-env and docker roles

roles/docker/tasks/install.yml

@@ -0,0 +1,45 @@
+---
+# Just use the same repo for cent7 and cent8 because ¯\_(ツ)_/¯
+- name: Install Docker repository
+  become: true
+  when: ansible_distribution == "CentOS"
+  yum_repository:
+    name: docker-ce-stable
+    description: Docker CE Stable - $basearch
+    file: docker-ce-stable
+    baseurl: https://download.docker.com/linux/centos/7/$basearch/stable
+    gpgcheck: false
+    gpgcakey: https://download.docker.com/linux/centos/gpg
+
+- name: Install Docker on Cent7
+  become: true
+  when: ansible_distribution == "CentOS" and ansible_distribution_major_version == "7"
+  yum:
+    # Update the cache to update with the new docker repo
+    update_cache: yes
+    state: latest
+    name:
+      - device-mapper-persistent-data  # Required for docker devicestorage driver
+      - lvm2                           #  same
+      - docker-ce
+      - containerd.io
+
+- name: Install Docker on Cent8
+  become: true
+  when: ansible_distribution == "CentOS" and ansible_distribution_major_version == "8"
+  dnf:
+    # Update the cache to update with the new docker repo
+    update_cache: yes
+    state: latest
+    name:
+      - device-mapper-persistent-data  # Required for docker devicestorage driver
+      - lvm2                           #  same
+      - docker-ce-3:18.09.1-3.el7
+
+- name: Install python bindings
+  become: true
+  pip:
+    name:
+      - docker==4.2.0
+      - docker-compose==1.25.4
+    state: present

roles/docker/tasks/main.yml

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+---
+- import_tasks: install.yml
+
+- name: Start and enable docker service
+  become: true
+  systemd:
+    name: docker
+    state: started
+    enabled: yes
+
+- import_tasks: tasks/preprocess-users.yml
+
+- name: Add superusers to the docker group
+  become: true
+  user:
+    name: "{{ item.name }}"
+    groups: docker
+    append: yes
+  loop: "{{ _users_local_admin }}"