Add a tool for computing groundtruth for a runbook

[magdalendobson]

The groundtruth computation tool in the deprecated C++ repository seems to have some bugs, so I wrote a new one in Rust using our Runbook abstractions. To avoid making diskann-tools take a dependency on diskann-benchmark-core, I moved some of the shared runbook code to diskann-utils.

Once this PR lands I will update the streaming groundtruth tool in big-ann-benchmarks to use the Rust code instead.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 49.07652% with 193 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.91%. Comparing base (62e201a) to head (bea772b).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...ann-tools/src/bin/compute_streaming_groundtruth.rs	0.00%	152 Missing ⚠️
...n-utils/src/streaming/executors/bigann/validate.rs	80.35%	33 Missing ⚠️
diskann-utils/src/lib.rs	53.33%	7 Missing ⚠️
...nn-utils/src/streaming/executors/bigann/runbook.rs	80.00%	1 Missing ⚠️

❌ Your patch status has failed because the patch coverage (49.07%) is below the target coverage (90.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1263      +/-   ##
==========================================
- Coverage   90.16%   89.91%   -0.26%     
==========================================
  Files         509      509              
  Lines       97234    96788     -446     
==========================================
- Hits        87672    87027     -645     
- Misses       9562     9761     +199     

Flag	Coverage Δ
miri	89.91% <49.07%> (-0.26%)	⬇️
unittests	89.58% <49.07%> (-0.26%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
diskann-tools/src/utils/ground_truth.rs	42.28% <100.00%> (ø)
diskann-utils/src/streaming/api.rs	100.00% <100.00%> (ø)
...nn-utils/src/streaming/executors/bigann/parsing.rs	83.68% <100.00%> (ø)
...nn-utils/src/streaming/executors/bigann/runbook.rs	79.13% <80.00%> (ø)
diskann-utils/src/lib.rs	74.07% <53.33%> (-25.93%)	⬇️
...n-utils/src/streaming/executors/bigann/validate.rs	80.35% <80.35%> (ø)
...ann-tools/src/bin/compute_streaming_groundtruth.rs	0.00% <0.00%> (ø)

... and 9 files with indirect coverage changes

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