Propagate number of processors from Transformations or Productions down to Jobs description

Nowhere in the TransformationSystem it is called `Job().setNumberOfProcessors()`. This is "correct", because the logic can be added to the ProductionSystem ("can an application/step run multicore?" and "what are its limits?").
Still, this is quite VO-dependant, but if any it should be added to Vanilla DIRAC ProductionSystem.

All considerations above are also valid for setting RAM limits, which is introduced in https://github.com/DIRACGrid/DIRAC/pull/8232