Finalize the integration of Code Generation

[CamilleLetavernier]

Original issue: eclipsesource/ecore-glsp#130

Currently, the code generation only exists in a work-in-progress branch. We need to finalize the integration of that branch. The main issue with the current branch is that is requires a pre-deployed Eclipse Application containing at least the EMF CodeGen Applications.

There are two approaches for this:

• Short term: maybe use the minimal EMF Product defined in 33: Add an Eclipse Product with EMF Codegen applications eclipsesource/ecore-glsp#120
• Mid term: provide a set of Ecore-related (non-GLSP) backend services and communicate with this backend server with Sockets (Rather than starting a short-lived Eclipse/Java-app each time)