Add momentum reslution measurement and resolution smearing functionality

For high-pT muons, we recommend to smear the muon momentum values in MC to take the systematic uncertainty on the resolution into account. In addition, we often recommend smearing the central values in the endcaps so that MC better matches the data. For this, we need to provide the momentum resolution as a function of momentum to analyzers. The functionality to measure this by fitting the momentum residuals in MC is added in the MR. In addtion, it adds the functionality to smear the momentum values in MC according to the recipe so we can validate the smearing recommendations. This implementation was done by @yibo, who is currently on vacation.

I have also added the last missing piece, the Z-pT binned DY samples. To get good results we need to properly stitch these samples by scaling them to lumi and cross section so we get a smooth muon pT distribution. I have hacked this functionality into the code for this set of samples. We can discuss if we want to make this into a general feature of the code. For now, I have written the cross sections into the "luminosity" entry in the dataset registry so we don't need to change all the registry to add cross section entry.

One thing I noticed now is that for high pT we are juggling different MC samples for different measurements, and currently that requires changing the dataset_allowed_definitions.py to put them in the order we need them. We should think about this selection to the json config files to make it easier to select the right MC sample for each part of the measurements.