Adds landing page for docs.openstack.org/ops

For new Operations Guide.

Patchset adds tracking for outbound links.
Patchset reverts changes to www/index.html.
Patchset flips the columns to avoid overlap.
Patchset adds .pdf download, lulu blue button, and explains mobi.
Patchset changes links to profile page rather than direct download.
Patchset emphasizes the membership is free.
Patchset adds DOCTYPE header for IE compatibility.
Patchset reverts to direct download and renames the PDF file for
consistency.
Patchset adds front and back covers to the PDF.

Change-Id: I096efd41cf45df03cf01bf5115172f80179b3800
Merge "Adds landing page for docs.openstack.org/ops"