Obtain a more accurate estimate of CPU resources for the simulated NSB levels

[tobiaskleiner]

The current estimates for CPU resources per event use the values from Prod6 (north only for now). In Prod6 we run both dark and half-moon conditions in the same job, so the CPU estimates include both. For the purpose of the resource estimate tools, that is not good since we would need the CPU per event for a single NSB level, not two (a more likely scenario for tailored simulations).

At the moment we decided to simply reduce the CPU estimate by 20% based on past experience. However, a more accurate estimate for the reduction factor should be obtained by running a test production with just half-moon conditions.

A similar strategy was taken also for estimating the resources for the Alpha layout compared to the hyper-array simulated in Prod6.