Add multi-vari distance calculation

[evanna00]

PR Checklist

• [x] This comment contains a description of changes (with reason)
• [x] Referenced issue is linked
• [ ] If you've fixed a bug or added code that should be tested, add tests!
• [x] Documentation in docs is updated
• [x] docs/changelog.md is updated

Description of changes

Calculate the multi-vary distance and specify the outliers.

Related Issues

Issue https://github.com/ewels/MegaQC/issues/433

[multimeric]

• [ ] We already had outlier detection previously. The change you made is more broad than that. Please update the title/description accordingly.
• [ ] Please follow the checklist above and ensure you've completed all those things, including adding a test! I can help you with this
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