Cleanup Domain Utilities

[HeikoKlare]

We have several redundant, duplicated or misplaced utilities for PCM, Java or their consistency preservation.
We have to clearly separate utilites for the individual metamodels (which have to be defined in the domains projects) and those for the consistency preservation between them, which have to be defined in the applications. We also have to eliminate duplications of utilities.

[HeikoKlare]

We also cross-use some of the utilities, e.g., test utilities for the individual applications used in the transitive change tests.
We should also consider this during refactoring to have one place where shared utils are placed (the domain-specific retrievals and modifications in the domains and the test-specific utilies in according shared projects).
We can then also declare the test projects as fragments of the projects they test, which is currently not possible to be able to reuse utilities of the test projects within others (see #84).