Install and configure OpenStack Dashboard (Horizon).
Horizon runs on port 80 behind Apache using mod_wsgi.
Configuration
We use the keystone.host key to connect to Keystone and horizon.secret_key
as the Django secret key.
The Django sessions storage backend is set to LocMemCache by default. If
horizon.caches.memcached is found instead not empty, the sessions storage
backend is set to Memcached and the control nodes are configured as memcached
locations.