Remove xtext postprocessors for compatibility with newer versions of Xtext generator
The deprecated xtext postprocessor functionality is now removed from xtext (checked with 2.28). The postprocessors should be removed so that etrice can be migrated to newer versions of xtext. Some of the postprocessors inject additional features into the inferred ecore metamodel, which means that any code using the injected api will not compile anymore.
DocuPostprocessor (adds genmodel documentation for EClasses and EFeatures)
- migrate documentation elsewhere (directly as comments in xtext model?)
ImplPostprocessor (adds operations etc. to xtext inferred ecore metamodel)
- move api to e.g. helper classes
- find all references and migrate to use helper classes (projects external to etrice?)