Add loop control label for apps and instances

This does not actually do anything right now, since the combination of
loop_control and (include|import)_*, but in 2.6.y or 2.7 it should work.

For reference: https://github.com/ansible/ansible/issues/42301

uwsgi-python/defaults/main.yml

----
-# files: uwsgi-python/defaults/main.yml
-
-uwsgi_name: uwsgi
-uwsgi_user: uwsgi
-uwsgi_group: uwsgi
-uwsgi_home: /var/www
-uwsgi_path: /var/www
-uwsgi_program: server.py
-uwsgi_callable: app
-uwsgi_command: runserver
-uwsgi_db: none
-uwsgi_python: 3
-uwsgi_mules: 0
-uwsgi_mountpoint: /
-uwsgi_enable_threads: false

uwsgi-python/tasks/main.yml

@@ -38,6 +38,7 @@
   with_items: "{{ webapps }}"
   loop_control:
     loop_var: app
+    label: "{{app.app}} {{app.instance}}"
   tags:
     - uwsgi
     - webservices