PlotModelHistory with MSE

Plot major and minor branch MSE in the same way like PlotModelHistory does for losses.

changed milestone to %Post-Processing

mentioned in commit 2f1806ff

assigned to @leufen1

added 58m of time spent at 2020-01-20

added 10m of time spent at 2020-01-22

added 1h 18m of time spent at 2020-01-23

added Doing label

added merged in Develop label and removed Doing label

mentioned in commit 6db0375f

closed via merge request !37 (merged)