(feature request) bhTree-based navigation for end to end tests

[jniles]

The current end-to-end test suite uses the URL to navigate to routes. This sometimes misses bugs when the tree and the URL are not hooked up properly (see: #701). Obviously, if the tree doesn't work, nothing really works in bhima.

It would be nice to navigate our tests suites via the tree. I propose that we keep our test interface helpers.navigate(DESTINATION), but instead of using the URL to route, this will click links in the bhNavigation component. This way, we can guarantee that the application behaves correctly as a user would use it.