Allow system properties abstraction

[TomaszGaweda]

This PR allows building abstractions very similar to SystemPropertiesExtension.

The use case in my case is related to Hazelcast (#hazelcast/hazelcast), where we have our class wrapper for ClusterProperties - ClusterProperty. Cluster properties can be set via system properties.

It's common to see then patterns like System.setProperty(SOME_PROPERTY.name(), "value") in the code. We are now slowly migrating to JUnit 5 and it would be awesome if we could use @SetSystemProperty - however, Java does not allow us to call .name() method in annotation.

With this PR merged we will be able to make similar annotations like:

@SetClusterProperty(LOGGING_TYPE, "log4j2")

Obviously it is possible to make such extensions right now, however it will duplicate existing extension - I'd even say, only changes will be other annotation names. I think there will be more places where libraries would like to have derivatives of the SetSystemProperty & Co. annotations.

Notes to reviewers:

• AbstractSystemPropertiesExtension is mostly a copy of old SystemPropertiesExtension
• new SystemPropertiesExtension implements AbstractSystemPropertiesExtension with current and standard set of annotations
• There is a test added SystemPropertiesExtensionViaCustomAnnotationTests, which is also mostly copied from SystemPropertiesExtensionTests, testing new abstraction and showing the usage.
• Please let me know if documentation added is enough. I didn't write too much as it's only a technical abstraction, that I think everybody will see quickly how it works, but I am not sure.

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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

[TomaszGaweda]

Thanks @mpkorstanje for adding the labels and forwarding to the Team. Please let me know when you will need changes to the PR, questions answered or anything else. Have a great day!