Resolve "Implement a multiplot that can flexibly call various plot functions"

This MR implements the multiplot function in the multiplot.py module.

The multiplot can apply multiple functions, specified in the _MULTIPLOT_PLOT_KINDS dict, consecutively on an axis.

Details

Currently, all seaborn plots having an ax kwarg, so taking an axis and not creating a figure themselves, are available. They were looked up in the seaborn API.

As a few examples of the plot configuration and capabilities, here is an extract from the test configurations:

multiplots:
  simple_scatter:
    plot_func: multiplot
    to_plot:
      - function: sns.scatterplot
        data: !dag_result data
        x: dim_0
        y: dim_1
        marker: x

  multiple_funcs:
    plot_func: multiplot
    to_plot:
      - function: sns.lineplot
        data: !dag_result data
      - function: sns.scatterplot
        data: !dag_result data
      - function: sns.despine

  # Try to plot all different plot kinds.
  # All plot functions should be available, but single plots are allowed
  # to fail. The plot should succeed.
  all_succeeding_sns_funcs:
    plot_func: multiplot
    to_plot:
      - function: sns.scatterplot
        data: !dag_result data
      - function: sns.lineplot
        data: !dag_result data
      - function: sns.histplot
        data: !dag_result data
      - function: sns.kdeplot
        data: !dag_result data
      - function: sns.ecdfplot
        data: !dag_result data
      - function: sns.rugplot
        data: !dag_result data
      - function: sns.stripplot
        data: !dag_result data
      - function: sns.swarmplot
        data: !dag_result data
      - function: sns.boxplot
        data: !dag_result data
      - function: sns.violinplot
        data: !dag_result data
      - function: sns.boxenplot
        data: !dag_result data
      - function: sns.pointplot
        data: !dag_result data
      - function: sns.barplot
        data: !dag_result data
      - function: sns.countplot
        data: !dag_result data
      - function: sns.heatmap
        data: !dag_result data
      - function: sns.despine
      - function: sns.regplot
        data: !dag_result data
      - function: sns.residplot
        data: !dag_result data

Extensions

• There should be a follow-up issue allowing for multi-axis support enabling plotting multiple functions on multiple axis.
• Possibly, we could enable animation support.
• Integrate plots from more plotting libraries? If yes, which ones?
• Extend the documentation entry by an example plot showing an example plot configuration and Ipython to load one of seaborn's example datasets and show the resulting plot in the documentation.

Anything to double-check?

• seaborn required version ok in the dependencies?
• matplotlib plot function selection ok? Reference link ok (I could not find an overview page of all available plot functions)?
• Include multi-axis documentation already or rather remove it?

Can this MR be accepted?

• Implementation ready
  • Add seaborn to the dependencies
  • Add a _MULTIPLOT_PLOT_KINDS dict containing all available function name -> plot function mappings
    • Inlcude seaborn plot functions
    • Include common matplotlib.pyplot plot functions
  • Implement the multiplot function in the multiplot.py module.
• Tests added or adjusted
• Documentation extended or updated

• Code quality
  • Changes follow coding guidelines
  • Checked code coverage on new and adjusted code

• Ready for merging
  • Pipeline passes without warnings
  • History cleaned-up or squash option set
  • Changelog entry added
  • Version number bumped
  • Reviewed & approved by @blsqr

Related issues

Closes #227 (closed)