Migrate Examples to Altair

[reidjohnson]

Altair is lovely.

[codecov]

Codecov Report

Attention: 6 lines in your changes are missing coverage. Please review.

Comparison is base (95e1a4f) 98.85% compared to head (efdef85) 98.77%.
Report is 1 commits behind head on main.

❗ Current head efdef85 differs from pull request most recent head efc23dd. Consider uploading reports for the commit efc23dd to get more accurate results

Files	Patch %	Lines
quantile_forest/tests/examples/__init__.py	33.33%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #31      +/-   ##
==========================================
- Coverage   98.85%   98.77%   -0.08%     
==========================================
  Files           4       13       +9     
  Lines        1044     1471     +427     
==========================================
+ Hits         1032     1453     +421     
- Misses         12       18       +6     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.