Create extensions with postgresql_ext instead of using psql

[gclough]

Ansible has a native module to handle PostgreSQL extensions called postgresql_ext:

http://docs.ansible.com/ansible/latest/postgresql_ext_module.html

We should use that, instead of calling shell, which then calls psql.

[gclough]

I tested this on the normal extensions part, and it seems to work:

- name: PostgreSQL | Add extensions to the databases
  postgresql_ext:
    db: "{{ item.0.db }}"
    login_user: "{{ postgresql_service_user }}"
    port: "{{ postgresql_port }}"
    name: "{{ item.1 }}"
  with_subelements:
    - "{{ postgresql_database_extensions }}"
    - extensions
  register: result

Who can test it for the rest of the cases (hstore,postgis, etc.)

[taybin]

What's the status of this?

[gclough]

This should be closed, as it was fixed in #307.