Revisit nf.explode() for multiple columns and duplicated index

[hombit]

I’ve actually been working on my own implementation of NestedFrame.explode in parallel with #327. Here I merge the two implementations but keep the test suites separate, since they cover different cases

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.13%. Comparing base (46acb8e) to head (95abd2e).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #332      +/-   ##
==========================================
+ Coverage   98.11%   98.13%   +0.02%     
==========================================
  Files          18       18              
  Lines        1748     1774      +26     
==========================================
+ Hits         1715     1741      +26     
  Misses         33       33              

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[github-actions]

Before [46acb8e]	After [fce18a4]	Ratio	Benchmark (Parameter)
879M	938M	1.07	benchmarks.ReadFewColumnsS3.peakmem_run
30.8±0.7ms	31.3±0.4ms	1.02	benchmarks.AssignSingleDfToNestedSeries.time_run
10.3±0.09ms	10.4±0.05ms	1.01	benchmarks.NestedFrameQuery.time_run
250M	250M	1	benchmarks.AssignSingleDfToNestedSeries.peakmem_run
135M	135M	1	benchmarks.CountNestedBy.peakmem_run
101M	102M	1	benchmarks.NestedFrameAddNested.peakmem_run
106M	106M	1	benchmarks.NestedFrameQuery.peakmem_run
105M	105M	1	benchmarks.NestedFrameReduce.peakmem_run
270M	270M	1	benchmarks.ReassignHalfOfNestedSeries.peakmem_run
1.22±0.01ms	1.21±0.01ms	0.99	benchmarks.NestedFrameReduce.time_run

Click here to view all benchmarks.

[Graciaaa3]

I think it looks great! The extension to more general behavior is definitely more helpful :)

[Graciaaa3]

I think it looks great!