[OpenPower-Firmware] op-test-framework documentation!

[Stewart Smith]

https://open-power.github.io/op-test-framework/

which is auto-generated from the python-sphinx docs both in some source
files and in the doc/ directory.

Currently, things are very, VERY, *VERY* incomplete (i.e. contain about
no content whatsoever).

This should probably change: patches welcome!

-- 
Stewart Smith
OPAL Architect, IBM.