Horizon container implementation

Horizon requires that Nova, Neutron(Nova Network), Glance,
and Keystone are running.  Therefore, the container needs to
check for the availablity of each service on startup.

The config file is not a .ini file, but rather a python file
so it requires using sed instead of crudini.

Change-Id: I5ed14514881fe9aef688ca08bcb94881ef5b25cb
Merge "Horizon container implementation"