Update documentation

The goal of this patch is to setup infrastructure and organization
of docs in the project.

Changes:
* Modified README to be similar to other OS projects
* Added project description to the index page
* Added install and run guide

Note(1):
These docs will be auto-published to http://ci.openstack.org/storyboard
after each merge very soon.

Note(2):
To build docs locally run in console:
$ tox -e docs
and open doc/build/html/index.html

Change-Id: I08b57117f90f3e4614bfa5c47020e40a6c26ff65
Merge "Update documentation"