Fixing some small issues

Summary

This MR introduces the following changes

• Fixing some naming issues in the plotting_umami.py example configs + docs.
• Init a default train config with default values if the loaded one does not have these.
• Re-ordering the lines in the Rejection per epoch plots from plotting_epoch_performance. Taggers loaded from files are now plotted first, then the taggers from local trainings and last the model which is to be plotted.
• Fixing some types and remove some pylint ignores which are not needed anymore.
• Fixed the usage of trained_taggers and taggers_from_file. trained_taggers was not used correctly and the label from taggers_from_file was not correctly loaded.

Conformity

• Changelog entry
• Documentation
• Development guidelines
• Style guides