Do not set failOnValidationError to no

These two guides are the only guides using it, let's remove the setting
to find bugs early.

Change-Id: I826e14975f8954fa80256e5bb41066d1d7b2ecdf
Add preface with revision history for Install Guide

Change-Id: I906dc60203cd782ab23135b14321fe6ce8821381
Merge "Do not set failOnValidationError to no"
Added Aptira's Current Training Material

Added some images/diagrams.

Fixed whites spaces and unusual characters,
as of short links and repeting doc contents
Sean Roberts has asked me to ignore it for
the moment as it will be done during Training
Docs Sprint on Wed 11 Sept.

Fixed a broken link

    >Most of the XML files are just templates
    >to be filled in later on. This commit is
    >kept lighter just to save the trouble of
    >re-modifying huge chunks of docs, just in
    >case theres an issue with the way its
    >formatted.

bp/training-manuals

Change-Id: I1919e5145322d5f5a49cc08a2bcfa7f65cf19cbe
Merge "Add preface with revision history for Install Guide"
Merge "Added Aptira's Current Training Material"