Support --select-module test discovery selector

[mpkorstanje]

With #1867 done it becomes possible to add code that interacts with the module path and scan modules for feature files. Our current implementation of the JUnit Platform Engine doesn't support this yet.

See:

• https://github.com/junit-team/junit5/blob/master/junit-platform-engine/src/main/java/org/junit/platform/engine/discovery/ModuleSelector.java
• https://github.com/junit-team/junit5/blob/3f7fed61f2edcee2a5551dbde75382b1dbe21267/junit-platform-commons/src/main/java9/org/junit/platform/commons/util/ModuleUtils.java

Open question: How do we support this in core?

[mpkorstanje]

Maven's support for multi-version modules still isn't great. Postponing this for now.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in two months if no further activity occurs.