Adds support for tree annotations with coloring and min, max attributes

[Julius-Plehn]

This PR adds the possibility to plot trees with an additional tree annotation

New features:

• It is possible to specify a column that is used to add annotations to the tree. Additionally, it is possible to specify either a colormap, a list of colors to cycle through, or a direct mapping as a dictionary which maps the available annotations to a color.
• Option to overwrite min and max values, which are extracted from the metric columns by default. This can be helpful if multiple trees should be compared at the same time, so that they share the same coloring schema.