Add support to reciving open test events and translate them in calls to the API of the new JUnit View

[laeubi]

We have the new org.eclipse.unittest.ui unit test view that can display unit test results in a vendor agnostic way (e.g. not bound to JUnit specifically).

There is also a Open Test Reporting API that also is vendor neutral, so this seems like a perfect fit.

To make integration of both things more convenient for the user we should do the following:

• create a new bundle org.eclipse.unittest.ui.ota4j
• create a bridge there that accepts a reader and read events according to the core.xsd and events.xsd
• translate them into calls of our API to update the view using a Stax Stream reader based approach to keep memory footprint low and to account for the stream based nature of these events.