Some Entity cleanup

[SJuliez]

Code updates for Entity in the hope of making it shorter and removing warnings

• removes almost all unused methods
• code updates like new switch statements and instaneof pattern variables, most of them one-click suggestions by the IDE
• other updates to remove warnings like incomplete javadoc

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 29.09%. Comparing base (07a8bb0) to head (96e1119). Report is 16 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #6004 +/- ## ============================================ + Coverage 29.07% 29.09% +0.02% + Complexity 13958 13957 -1 ============================================ Files 2576 2576 Lines 267398 267183 -215 Branches 47803 47718 -85 ============================================ + Hits 77735 77737 +2 + Misses 185761 185541 -220 - Partials 3902 3905 +3 ```

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