Documentation Enhancements

Added links to instructions for running functional tests.
Added links to information about contributing to Solum.
Reworked the devstack README file.
Rewrote the Getting Started Guide.
Added a local.conf file and setup_devstack.sh file.

Change-Id: Idfbf6b1fd7cd75aaab8fc56e7717605343a5c31f
Merge "Documentation Enhancements"