REVIEW-4722: Renamed artifact types
REVIEW-4728: Use correct pattern (including 'type') for layout of type 'ivy'

- Added javadoc for 'ivy' layout.
REVIEW-4730: Use the ivy module fixture for testing repository layouts

- Allow the patterns to be updated on ivy module fixture
- Fixed fixture so that it correctly handles patterns that include nested directories
Switched a few integ tests to use the ivy module fixtures