Easier input generation

[maxbechtold]

Currently, inputs are to be created based on an index. This requires the test setup to (deterministically) build inputs from the index. It should prove useful to explore generators like those of JQwik to "smartly" create inputs.

It is then the user's responsibility to register those inputs with the goldenmaster JUnit extension to bring them together with the outputs. Something like File output = goldenMaster.register("input-representation", inputObject) perhaps?

Thanks @BlueIce, @rolandsand, @JanMuellerAndrena, @deeteear for the fruitful discussion!