Provide a module-info file

[nils-christian]

The framework uses currently Java 11. It should at least be discussed if a module-info file should be therefore included. Some of the used libraries (like apiguardian or log4j-api) include one as well. Such a module-info file would have to be maintained though.

This could be a starting point:

module archifacts.core {
	
	requires com.tngtech.archunit;
	requires org.apache.logging.log4j;
	
}