Changed docker to use a hosts file with various var files and to use roles.

docker/hosts

@@ -0,0 +1,14 @@
+#   - Comments begin with the '#' character
+#   - Blank lines are ignored
+#   - Groups of hosts are delimited by [header] elements
+#   - You can enter hostnames or ip addresses
+#   - A hostname/ip can be a member of multiple groups
+
+[barker]
+pkl ansible_host=beacon var_file=vars/pkl.yml
+chd ansible_host=beacon var_file=vars/chd.yml
+mhl ansible_host=beacon var_file=vars/mhl.yml
+# hin ansible_host=beacon var_file=vars/hin.yml
+
+[all:vars]
+ansible_python_interpreter=/usr/bin/python3