Removes basic-install-guides from training guides

As per the discussion in the Kilo summit, the POC part was done for
basic install guides and there is no need to maintain or keep the
XML files in the repository. This is a clean up patch which is
mandatory for Icehouse release for training guides.

Change-Id: I7e5f2bbce86e0bdd292f0cb8b395995f9171e5eb
Merge "Removes basic-install-guides from training guides"