Implement metapostprocessing jupyter notebooks

[ankitpatnala]

• [x] Box-plots for comparing different models in terms of specific metrics (Fig. 2 d in ICLR poster)
  • [x] Line-plots showing the metrics of different models against daytime (see Fig 13 in D1.4 of the MAELSTROM project)
  • [x] Energy spectra for multiple models
  • [x] Difference plots for model-to-model intercomparison
  • [x] Plots from several models for case studies -> visual comparison for specific dates
  • [ ] Visulaize results of Mann-Whitney U-test in box-plots (cf. #20)