Improve ghoul behaviour (rebase+fix) (#3230)

* Improve ghoul behavior

* Fix rebase errors

* Ghoul: overall quality
closes #2848

* Implement RustyBox's art and behaviour

* ghoul: tweak values

* Ghoul: thrust horizontally

* Ghoul: fix negative thrust

* Ghoul: add [[fallthrough]] where needed

* Ghoul: Remove unnecessary variable

* Ghoul: remove unnecessary properties

* Ghoul: code style

* Ghoul: remove speed option

* ghoul.cpp: fix indentation

* ghoul: fix gramar to fit arbitrary contraints

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Co-authored-by: Daniel W <[email protected]>

Author: Hypernoot