roles/taiga: Deploy Taiga project management app

The *taiga* role installs the three components of Taiga:

* taiga-back
* taiga-events
* taiga-front

*taiga-back* is a Python application. Its dependencies are installed via
`pip` in the *taiga* user's site-packages, and the application itself is
installed by unpacking the archive. *taiga-events* is a Node.js
application. Its dependencies are installed by `npm`, and is itself
installed by unpacking the archive. Finally, *taiga-front* is a
single-page browser application that is installed by unpacking the
archive, and served by Apache.

Taiga requires PostgreSQL and RabbitMQ.

roles/taiga/tasks/rabbitmq.yml

@@ -0,0 +1,14 @@
+- name: ensure taiga rabbitmq vhost exists
+  rabbitmq_vhost:
+    name=taiga
+    state=present
+- name: ensure taiga rabbitmq user exists
+  rabbitmq_user:
+    name: taiga
+    password: '{{ taiga_events_password }}'
+    permissions:
+    - vhost: taiga
+      configure_priv: .*
+      read_priv: .*
+      write_priv: .*
+    state: present