Visualization of correlation length for time series

[marinaevers]

Visualize the correlation length of a single time series as proposed here: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10433771. Therefore, we want a function
plot_correlation_length(time_series, seed=55, fig=None, axs=None, colorblind_safe=False, show_plot=False, **kwargs),
where time_series is an object of the TimeSeries class. The other parameters are consistent with the other plotting functions. The current interface for time series can be found in the corresponding branch.
The x-axis should use the time steps.

This function should also be shown in the example notebook created in issue #30.