Refactoring: Use lombok for simple getters & setters

[Philzen]

As Lombok is available throughout the project and also used in a couple of places, we can use it to remove several thousand lines of boilerplate code. This PR applies mostly @Getter and @Setter annotations wherever feasible, while not replacing any getter or setter methods that already have annotations (which could be facilitated via the onX meta-annotation, however for now refraining from using it as it is still experimental).

This makes the code base and – most importantly – the cognitive complexity to work through the repo considerably smaller. Also the declarative approach has the advantage that one can see immediately if a field is exposed in the public API by just looking at the declaration annotation.

This PR also contains some Javadoc and @Override annotation fixes and removes identical implementations in inherited classes.

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[Philzen]

@wing328 This PR was lying dormant for over two weeks as it appears the automatically assigned reviewer is unavailable. I've now rebased everything on main master – would you be able to take over for a review here?

Would love this to go in first so i can rebase my other open PRs on it (as it greatly simplfies things with ~3500 LOC saved).