Upgrade to new Xtext code generation workflows

[lwrage]

Summary

Xtext has an updated the code generation workflows. The old generator is deprecated and scheduled to be removed in Xtext 2.23. We need to upgrade all workflows (AADL, ALISA, EMV2).

Resources

https://blogs.itemis.com/en/how-to-reference-uml-elements-from-xtext-dsls

Environment

• OSATE Version: 2.8.0
• Operating System: all

[lwrage]

Using a new workflow just for an annex does not work with code completion (#1818). Need to run an experiment to see if that works after upgrading AADL workflow.