feat(vis-violin): violin vis subcategories and proper facets

[dvmartinweigl]

Closes https://github.com/datavisyn/bioinsight/issues/437

Developer Checklist (Definition of Done)

Issue

• All acceptance criteria from the issue are met
• Tested in latest Chrome/Firefox

UI/UX/Vis

• Requires UI/UX/Vis review
  • Reviewer(s) are notified (tag assignees)
  • Review has occurred (link to notes)
  • Feedback is included in this PR
  • Reviewer(s) approve of concept and design

Code

• Branch is up-to-date with the branch to be merged with, i.e., develop
• Code is cleaned up and formatted
• Unit tests are written (frontend/backend if applicable)
• Integration tests are written (if applicable)

PR

• Descriptive title for this pull request is provided (will be used for release notes later)
• Reviewer and assignees are defined
• Add type label (e.g., bug, feature) to this pull request
• Add release label (e.g., release: minor) to this PR following semver
• The PR is connected to the corresponding issue (via Closes #...)
• Summary of changes is written

Summary of changes

• added various features and improvements to violin vis
  • possibility to select subgroup column
  • create facets for data by selected column
  • added sort icons --> sort by mean (yAxis) and alphabetically (xAxis)
  • added possibility to sync the yAxis across subplots
  • added strip overlay with possibilty to select single points or whole violins
  • consistent style for selection state using opacity + group colors for selected violins
• added breast cancer dataset to cover more test and use cases for vis

Screenshots

Additional notes for the reviewer(s)

Thanks for creating this pull request 🤗

[dvchristianbors]

Thanks for your PR. I just made a tiny change, pulling the traces color into a constant. Otherwise, it looks good to me. I tested several permutations of the violin plot. And with the addition of the new breast cancer sample dataset, everything worked nicely (also some columns with missing data).

[dvdanielamoitzi]

@dvmartinweigl thanks for this PR, I have a few minor comments:

• please add a tooltip when the facets is disabled explaining why:
  

• Can we reduce the horizontal spacing a little? There's so much whitespace:
  

[dvchristianbors]

Violin plot stories are currently broken, this will be addressed in a follow-up ticket: #345

[dvdanielamoitzi]

• when we have split violins with 2 categories, and the left violin is null, the right violin takes the place of the left violin:
  

• we should consider the number of categories for the spacing when we do faceting. E.g. when we have more than 2 in a row / column, the space should be reduced. -> same for the scatter vis

• sorting by the category on the x-axis shows all categories, even if they are null. When the axis is unsorted, it correclty shows the right amount of categories. (As discussed with @dvmartinweigl this could be tricky and we'd create a follow-up ticket for it.)

[dvchristianbors]

Thanks for your final changes. The last issue that caused the violin plot not to be shown in Ordino now properly works. From my point of view, this PR can now be merged.