diagrams redrawn
Updated images
Updated docs with the actual configuration scenarios
Added OSTF section
Formatted text, removed nagios
Cosmetics
Merge branch 'fuel-3.1' of github.com:Mirantis/fuel-docs into fuel-3.1

Conflicts:
	index.rst
	pages/about-fuel/0030-how-it-works.rst
	pages/about-fuel/0040-reference-topologies.rst
	pages/about-fuel/0060-download-fuel.rst
	pages/installation-fuel-cli/0057-prepare-for-deployment.rst
	pages/installation-fuel-cli/0060-understand-the-manifest.rst
	pages/installation-fuel-cli/0070-orchestration.rst
	pages/installation-fuel-cli/0080-testing-openstack.rst
	pages/installation-fuel-ui/install.rst
	pages/installation-fuel-ui/networks.rst
	pages/production-considerations/0030-large-deployments.rst
	pages/production-considerations/0040-post-install-healthchecks.rst