x-maturity and complex info.x-trapi.test_data_location aware

• back end engine and web service API (but not yet UI) is fully x-maturity aware
  • /registry reports (lists of) x-maturity associated with KP and ARA resources
  • /run_tests accepts an optional x-maturity constraint (otherwise defaults to one sensible x-maturity per test run)
  • diverse reports now report x-maturity
• back end engine gracefully deals with diverse complex info.x-trapi.test_data_location specs
  • x-maturity constraints drive test data selection
  • lists of test data files (from lists of test data urls) are merged into single test edge data runs