do not allow modules to import unsafe engine classes

[keturn]

The Malicious module detected a regression in #4622 that allows modules to import any class in the org.terasology.engine package.

Related: MovingBlocks/gestalt#112

It would help to have a test for this as part of the normal automated test suite that doesn't require manually launching a game and searching the logs.

[keturn]

I stashed some work in progress where I was experimenting with this at keturn@e95fc8d

[keturn]

Ah, at least part of why I didn't want to merge that WIP commit as-is is because there are some refactorings in there like static Module loadAndConfigureEngineModule(…) that I didn't actually end up making use of.

(because as I wrote tests, it became clear that the tests I was trying to write depended upon the combination of that and stuff from setupSandbox and/or loadEnvironment)

and I'm not sure if the stuff I was trying to do with org.terasology.unittest.stubs was in a working state

[jdrueckert]

Fixed by MovingBlocks/gestalt#112