Visualization temporal attributes for nodes

[hackl]

Reintroduce the function from pathypy3 with time-varying node attributes (e.g., colors).

[M-Lampert]

Partly integrated in #267

[M-Lampert]

Will be added with #295 as follows:

g = pp.TemporalGraph.from_edge_list([("a", "b", 1)])
pp.plot(g, node_color={"a-1": "red", "a-3": "blue"})