edxaop_prod: add target for all prod appservers (edx-west)

playbooks/edx-west/edxapp_prod.yml

+- hosts: tag_environment_prod:&tag_function_webserver
+  sudo: True
+  vars_files:
+    - "{{ secure_dir }}/vars/edxapp_prod_vars.yml"
+    - "{{ secure_dir }}/vars/users.yml"
+    - "{{ secure_dir }}/vars/edxapp_prod_users.yml"
+  roles:
+    - common
+    - nginx
+    - gunicorn
+    - edxapp
+    - ruby
+    - npm
+    - edx-theme
+    # run this role last
+    - in_production