1. Update URLs according to document migration
2. Update the dead links
3. Optimize (e.g. http -> https)
Change-Id: I171ce5fcd437747fed07884d80db833cf3db2358
This patch added README file in devstack folder
and corrected the rally repository by changing from
stackforge to openstack
Change-Id: I40a61d0de26cc26464f65d21098c9aa93be4ad8b