- Major structural changes, so it now follows the same structural layout
  as EWAOL and Cassini documentation.
- Grammar fixes, text has been rewritten, content has been added.
- All broken links etc have been fixed.
- Links has been moved to the bottom of our documents instead of having
  them in-text.
- System architecture, user accounts and a few other pages has been
  added.
- Some diagrams has been replaced with PlantUML diagrams (natively
  supported by rst/Sphinx).

Signed-off-by: Joakim Bech <joakim.bech@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>