container: Support setting container hostname

roles/container/tasks/main.yaml

@@ -50,6 +50,7 @@
     mount: "{{ _container_mounts | map('items') | map('map', 'join', '=') | map('join', ',') }}"
     device: "{{ _container_devices }}"
     network: "{{ _container_networks_with_ip }}"
+    hostname: "{{ container_hostname or omit }}"
     publish: "{{ container_publish_ports }}"
     secrets: "{{ _container_secrets }}"
     env: "{{ container_env }}"