Replace deprecated "include" with "import_tasks"

https://docs.ansible.com/ansible/latest/user_guide/playbooks_reuse.html#playbooks-reuse

Author: martey

ansible/roles/common/tasks/main.yml

@@ -1,2 +1,2 @@
-- include: apt.yml
-- include: security.yml
+- import_tasks: apt.yml
+- import_tasks: security.yml

ansible/roles/web/handlers/main.yml

@@ -33,4 +33,4 @@
   tags:
     - fixtures
 
-- include: sentry.yml
+- import_tasks: sentry.yml

ansible/roles/web/tasks/main.yml

@@ -1,5 +1,5 @@
-- include: redis.yml
-- include: nginx.yml
-- include: letsencrypt.yml
-- include: django.yml
-- include: pretalx.yml
+- import_tasks: redis.yml
+- import_tasks: nginx.yml
+- import_tasks: letsencrypt.yml
+- import_tasks: django.yml
+- import_tasks: pretalx.yml