Updated operator guide documentation for
1. segregated sections appropriately
2. referred masakariclient for CLI section
3. added detailed 'Install and configure for Ubuntu' section
4. added detailed 'Verify operation' section
5. used sphinx-build instead of the pbr sphinx extention for building docs
as instructed by the PTI[1]
6. cleaned up build_sphinx related entries in setup.cfg
[1]: https://governance.openstack.org/tc/reference/project-testing-interface.html#documentation
Change-Id: Iec93bebdbc7ffe1ccd27bb11f474384ff06a559c
Shilpa Devharakar