Bugfix for setup.sh and add the user manual

Bugfix:
  - setup.sh uses python3 to run the script, so we should
    use pip3 to install the requirements package, otherwise
    the script will fail on module not installed.
    (And boot the virtualenv by python3)
  - changing the inventories configuration name to .yml
    the kubespray had updated and generated yaml instead of ini format
    and ansible parses the configuration according to extension name
  - Remove the docker version tag, 17.03 isn't exist on Ubuntu bionic's
    apt source, so I prefered not to assign the docker version and
    let Kubespray to choose.

Change-Id: I5f2ad2e9fb14880c16e8d7e8e8b55d1583f95e95
2 files changed