Rewrite of the `Base.getSettingsFolder()` and `Platform.getSettingsFolder()` by Stefterv · Pull Request #1335 · processing/processing4

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Rewrote both function so they fit into a single file, negating the need for hopping around when looking into what this functionality does.

Also rewrote it so it is no longer generates random awt windows through the `Messages` class

- Added the previous settings override in base again
- Added a system property to override the settings folder within tests

Introduces logic to detect a preferences.txt file in the same folder as the running executable or jar. If found, settings are loaded from this location, improving portability and allowing users to override default settings without modifying system directories.