Display test results.

Create a new webpage to display test results.
Show all testcases ran, their status (PASS/FAIL) and elapsed time.
Also, restructure tempest_subunit_test_result.py so that I can
derive my own class to create a dictionary tailored for the webpage.

Change-Id: I0a30f5584ab2c2b1ae36e0834afb3d26a284f1f0
Partially-implements: blueprint display-test-results