Update JUnit XSD to support additional data

[codito]

Current JUnit schema used by JunitXml.TestLogger is several years old. Here are the various formats used today.

• Jenkins Junit plugin docs are here. JUnit 5 project uses the Jenkins XSD from there.
• Gitlab JUnit parser (see attached junit example from issue) and CircleCI have added few additional elements to the schema for better reporting (reference). E.g. file in testcase element
• Testmo provides a comparison of various possibilities in the schema here.

Proposal

Work In Progress. Kindly share your inputs.

Support a Schema logger configuration with one of junit, jenkins. Few differences:

• jenkins allows non-empty properties node
• jenkins allows per test case system-out/err messages
• jenkins may be better suited for attachments support?

TODO: review if there any other differences between both?

Future

If needed, we can extend the ReportFormat=custom add the following capabilities

• file attribute in testcase
• properties in testcase to log relevant info like test category, description etc. E.g. NUnit Description option for Junit test reports junit.testlogger#48

Related issues

• Include stdout for tests that pass junit.testlogger#41 and Add system-err and system-out to testcase junit.testlogger#47
• Gitlab Attachments with .NET - XML missing attachment markup junit.testlogger#71 (comment)