Initial outline of Deployment documentation.

Will cover deploying with Apache, Nginx, Gunicorn, and uWSGI.

Refs #12279
Update getting started message for documentation.

Refs #12279
Fix references to RAPI, upgrade, and development

Refs #12279
Docs: Fix up organization and remove fabric info.

The fabric information is really outdated and completely unnecessary.
One FAQ item was salvaged from the fabric docs.

Refs #12279
Update dev requirements to install Sphinx and deps

Refs #12279
Fix title underline error in faq.rst

Refs #12279
Add in rst_epilog for |gwm|.

All documentation files are now able to use |gwm| as a substitute for
'Ganeti Web Manager' without needing to add the replace directive on
each page.

Refs #12279
Deployment steps now in own documentation file

The section in install.rst on deploying with apache + mod_wsgi has been
moved to the deploying.rst file.

Refs #12279
Change all index TOCs to have a maxdepth of 1.

Refs #12279
Fix identation on note about LDAP documentation.

Refs #12279
Update installation documentation.

Moved dependencies to own file under ref/.

Refs #12279
Change all :doc: directives to :ref:

Refs #12279
Replace '|project|' substitution with '|gwm|'.

Refs #12279
Missed virtualenv update for new path in deploying

Refs #12279
Rename usage directory to features in docs.

Refs #12279
Move all community and info docs under info.

Refs #12279
Rename 'Usage' header to 'Features'

Refs #12279
Moved intro documentation on cluster setup.

Moved documentation in 'usage/cluster' related to initial setup of
creating vms and importing orphans to 'importing'. Removed duplicate
information and added warning about read-only cluster mode.

Refs #12279
Move upgrading documentation under usage docs.

Created new header in index for Usage which is seperate from features.

Refs #12279
Added a lot of placeholder docs with TODOs.

This includes quite a bit of rearranging on the index page.

Added Usage section back, so there now exists both Usage and Feature
documentation.

conf.py now contains the default setting for todo_include_todos. This
can be set to True to generate documentation that displays todos. It
will not be picked up by sphinx-build though, so the build directory
will have to be rm-ed first.

Refs #12279