All plots: change default y axis limits on logit scale

[JonasKellerer]

The logit scale uses fixed y axis limits. Change this so the limits are

• for min: max(0.0001, min_of_data)
• for max: min(0.9999, max_of_data) by default.

Also add the possibility for the maintainer to set the limits to fixed values. The limits of the values should be: tbd.