Move application configuration to dedicated tasks file

[jpiron]

This allows to use the tasks_from option of the import_role module. This permits to install and configure logrotate basics in one playbook, and to configure application specifics in another application specific playbook with something like:

- name: "Configure log rotation."
  import_role:
    name: ansible.logrotate
    tasks_from: configure_application
  become: True
  vars:
    logrotate_applications: "{{ redis_logrotate_configurations }}"
  when: redis_logrotate_configurations is defined

for instance.