I am removing the Oomph setup from the project catalog

[merks]

The setup does not appear to be well maintained and is not currently functional:

https://github.com/eclipse-elk/elk/blob/master/setups/EclipseLayoutKernel.setup

I'll remove the reference to it with the next commit to Oomph project catalog on December 10th.

[soerendomroes]

Yes, most times it does not make sense to use only ELK in a setup. Hence, we are using a setup for multiple projects at once.