Add configure flag to enable hipcub
For nblk > 64 the HIPCUB implementation gives wrong results!
The old module-image for the shared runners will be discontinued on October 31. All users still referencing gitlab-registry.mpcdf.mpg.de/mpcdf/module-image in their CI pipelines need to switch to the new CI images now, see instructions here.
For nblk > 64 the HIPCUB implementation gives wrong results!