Introduce support for selecting packages, classes, and methods in ConsoleLauncher and Gradle plugin

[sbrannen]

Overview

#410 removed the generic name based selectors previously used by the DiscoveryRequestCreator.

Consequently, that deleted code has been relocated to DiscoveryRequestCreator as a private, internal implementation detail; however, this is only a temporary solution.

This issue therefore aims to provide a robust solution that will accommodate support for additional test artifact types other than Java based packages, classes, and methods.

Related Issues

• Introduce support for filtering packages #313
• Introduce support for selecting classpath resources in ConsoleLauncher and Gradle plugin #452
• Introduce support for selecting files and directories in ConsoleLauncher and Gradle plugin #453
• Improve naming of command-line options for ConsoleLauncher #468

Deliverables

• Introduce explicit support for selecting packages in ConsoleLauncher via -p | --select-package
• Introduce explicit support for selecting packages in the JUnit Platform Gradle plugin
• Introduce explicit support for selecting classes in ConsoleLauncher via -c | --select-class
• Introduce explicit support for selecting classes in the JUnit Platform Gradle plugin
• Introduce explicit support for selecting methods in ConsoleLauncher via -m | --select-method
• Introduce explicit support for selecting methods in the JUnit Platform Gradle plugin

[marcphilipp]

I've updated the issue's description and removed the java part of the long options to be in sync with our decision wrt. DiscoverySelectors for packages, classes, and methods.

[marcphilipp]

Done.