Yield tables

[alexander-held]

Add yield tables showing pre- and post-fit yields for the full model prediction per region. Also include yields per sample, and all predicted yields (total model and yield per sample) should include uncertainties.

It might be a good idea to split this up into two components: calculation of yields / uncertainties, and separately the creation of tables from this information (where many layouts are possible, and it should be possible to use a custom layout).

See also this discussion: scikit-hep/pyhf#1187

[alexander-held]

Calculation of yield uncertainties per channel instead of per bin requires some way of histogram re-binning (scikit-hep/pyhf#1198)

update: a cleaner solution is instead used in #189, which does not require re-binning

[alexander-held]

#159 enables yield tables built from the information needed for data/MC plots. Two more things have to be included still:

• uncertainties per sample (instead of only total model prediction)
• yields per region instead of per bin (requires a new calculation with a model that has bins summed per channel)

[alexander-held]

#189 will include yields per channel, with corresponding uncertainties. The remaining feature for yields per sample is being tracked in #191.