Xtext editors declare dependency on deprecated runtime library

The xtext editors shipped with Papyrus for Robotics declare a dependency to the deprecated library "org.eclipse.xtext.generator". In addition, they contain a non-required dependency to com.ibm.icu and miss the org.eclipse.emf.mwe2.lib. The first part of the issue implies that an error is shown when the xtext editor plugins are opened in an IDE having the xtext SDK installed.