721314 - add man pages for pulp-admin and pulp-consumer

Docs for pulp-admin and pulp-consumer already exist but were only being
rendered as HTML and not man pages.

This commit adds a build step to render the docs as man pages and adds them to
the spec file.

Note that intersphinx has temporarily been disabled. It makes calls to pull
down `objects.inv` files from readthedocs.org which is not allowed in some
build environments. I will add intersphinx back in with offline support as part
of the intersphinx support task. Note that this is only needed for platform;
the plugins do not generate man pages via `sphinx-build`.