Merge branch 'ec2-user' into 'master'

Adding ec2-user to systems group role

See merge request hpc-team/ansible_cluster_in_a_box!240

roles/ec2-user/tasks/main.yml

+- name: Add ec2-user to systems group locally
+  user:
+    name: ec2-user
+    groups: systems
+    append: yes
+  become: true
+  become_user: root