JDT Facade project

[LorenzoBettini]

In some parts, we use internal members of JDT or use reflection to perform different method calls according to the version of JDT (see #3128 and #3124)

Se also

• Remove obsolete compiler option assignments #3206
• replace obsolete reflection usage with original method calls #3205

We could confine such code in a separate project, acting as a facade for JDT. At least the code using reflection and internal JDT members is not spread over all our projects.

[LorenzoBettini]

The project was created and initial hacks were moved there.

I'll leave this open because there are other parts to be moved in the jdt.facade project