Add visualization for timeseries

[stefsmeets]

This PR implements a visualization for timeseries visualization. I tried to implement what seems to be the most common way of making these plots.

Currently it takes x, y and a bunch of segments that look like this:

from dianna.visualization import plot_timeseries

segments = [
    {'index': 0, 'start': 0, 'stop': 2, 'weight':-0.6},
    {'index': 1, 'start': 2, 'stop': 4, 'weight':-0.3},
    {'index': 2, 'start': 4, 'stop': 6, 'weight': 0.0},
    {'index': 3, 'start': 6, 'stop': 8, 'weight': 0.4},
    {'index': 4, 'start': 8, 'stop': 10, 'weight': 0.7},
]

x = np.linspace(0, 10, 20)
y = np.sin(x)

plot_timeseries(x=x, y=y, segments=segments, cmap='bwr', show_plot=True)

This is what it looks like:

I tried to keep the interface somewhat basic, because I expect this will need some finetuning after #476 and #490

Closes #457

[stefsmeets]

@cpranav93 Could you have a look and let me know what you think?

[cwmeijer]

Looks great and I also like the input format. I think it is perfect.
I don't suppose this works on multivariate time series right? That is totally fine, but I think the function title (or at least the doc string) should mention this.
Also, please fix the linting before merging. :-)
Great addition! 🎆

[cpranav93]

Looks great! As we expand the time-series functionality in Dianna we can add more methods for visualisation if necessary. Prospector seems to be failing for the build - maybe worth a look before merging.

[stefsmeets]

Oh, we are using pylint 😬 I will address this and then merge. Thanks!

dianna/visualization/timeseries.py
  Line: 7
    pylint: too-many-arguments / Too many arguments (9/5)
    pylint: too-many-locals / Too many local variables (16/15)

tests/test_visualization.py
  Line: 5
    pylint: missing-function-docstring / Missing function or method docstring
  Line: 18
    pylint: trailing-newlines / Trailing newlines

[stefsmeets]

@cwmeijer Multiviarate timeseries can be easily added later. I would suggest to add that once it is more clear what data needs to be plotted.

[cwmeijer]

I absolutely agree with adding multivariate functionality later. Please still update the doc string because who knows how many releases we will do before actually adding multivariate support.