A lot of links led to the Github wiki, which then redirected you back to the docs. Also, remove "Install Vagrant" option for raw packaging, because those users should be using vagrant-spk, and we introduce people to that first, including directing people to it at the top of this page.
This largely links to existing documents, rather than copies them wholesale
into docs/. Copying them into docs/ is a goal for the very near future.
This also changes the default them to one where the navigation is not
constantly visible at the top for non-wide screens (aka mobile).