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`.
Shouldn't we avoid checking in the man pages, similar to how we don't check in the rendered HTML? It seems like it would be better to only keep the source in here and let the spec file and devs run make man when they need man pages.