Create documentation for HippoUnit

[appukuttan-shailesh]

I have started on this. Shall make a pull request when I have something ready.

[appukuttan-shailesh]

First draft of documentation ready:
https://hippounit.readthedocs.io/

Currently, the tests, capabilities and scores are automatically identified and documented. The next step is to restrict the amount and type of information being displayed for each entry. This will also involve the task of generating documentation from source code through the use of type hints (and other possible means).

[appukuttan-shailesh]

Additional pages, including one that displays test info from HBP validation framework has now been included.

To do list:

• Display selected info for tests, capabilities and scores
• Design intuitive link from VF test library entries to test implementaton (handle multiple test instances)
• Implement type hints if necessary