Reduce Apache dependency in usb_lib & nginx roles

roles/usb_lib/tasks/apache.yml

@@ -0,0 +1,12 @@
+- name: Enable http://box/usb via Apache
+  command: a2ensite content_dir.conf
+  when: usb_lib_enabled | bool
+
+- name: Disable http://box/usb via Apache
+  command: a2dissite content_dir.conf
+  when: not usb_lib_enabled
+
+- name: (Re)Start '{{ apache_service }}' systemd service
+  systemd:
+    name: "{{ apache_service }}"    # apache2 or httpd, as set in /opt/iiab/iiab/vars/<OS>.yml
+    state: restarted

roles/usb_lib/tasks/main.yml

@@ -30,7 +30,13 @@
   when: usb_lib_installed is undefined
 
 
-- include_tasks: enable-or-disable.yml
+- name: Enable/Disable/Restart Apache if primary
+  include_tasks: apache.yml
+  when: not nginx_enabled
+
+- name: Enable/Disable/Restart NGINX if primary
+  include_tasks: nginx.yml
+  when: nginx_enabled | bool
 
 
 - name: Put variable in iiab.env that enables display of content at root of USB

roles/usb_lib/tasks/nginx.yml

@@ -28,10 +28,7 @@
     state: absent
   when: not usb_lib_enabled
 
-- name: Enable http://box/usb via Apache, if usb_lib_enabled
-  command: a2ensite content_dir.conf
-  when: apache_install and usb_lib_enabled
-
-- name: Disable http://box/usb via Apache, if not usb_lib_enabled
-  command: a2dissite content_dir.conf
-  when: apache_install and not usb_lib_enabled
+- name: Restart 'nginx' systemd service
+  systemd:
+    name: nginx
+    state: restarted