tailor default memory to dataset

[robertdstein]

Is your feature request related to a problem? Please describe.
I'm always frustrated when I start a job on the desy cluster, then it dies because the memory requested is insufficient. This is not a hard problem, to first order it scales with the size of the MC.

Describe the solution you'd like
A method to adjust the default memory request depending on the dataset MC. Maybe by checking the dataset MC file size without loading?

Describe alternatives you've considered
Leave it as is. It's not too annoying, you figure it out manually once per analysis.

[mlincett]

Is it correct to expect a memory consumption of (MC size) * (number of seasons) * (number of cores)?