Document configuration parameters for parallel test execution in Jupiter

[stoyanK7]

Overview

Partially addresses #2669.

Introduces a new table with relevant parallel execution properties in junit-platform.properties.

How the addition looks like

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Definition of Done

• There are no TODOs left in the code
• Method preconditions are checked and documented in the method's Javadoc
• Coding conventions (e.g. for logging) have been followed
• Change is covered by automated tests including corner cases, errors, and exception handling
• Public API has Javadoc and @API annotations
• Change is documented in the User Guide and Release Notes
• All continuous integration builds pass

[sbrannen]

This has been merged into main in 3818dce and revised in 2f0a502.

Thanks / Blagodaria!