Add simple DB server GUI

As a test designer, I want to be able to access the state of the db server through a graphical user interface showing me all stored information, so that I'm able to identify missing scenarios or adapt my tests to the existing ones.

The issue names no files, tests, or entry points; begin by reviewing the Java server implementation and how the simulated database state is represented. The work is done when a graphical interface provides access to all information stored by the database server for test-design use.

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