Add sparse histogram implementation

[camposandro]

Move the SparseHistogram implementation that currently resides in the importer to hipscat. LSDB will use it to compute the point map distributions more efficiently.

• [ ] My PR includes a link to the issue that I am addressing

Code Quality

• [X] I have read the Contribution Guide
• [X] My code follows the code style of this project
• [X] My code builds (or compiles) cleanly without any errors or warnings
• [X] My code contains relevant comments and necessary documentation

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 94.09%. Comparing base (405bebe) to head (4bdb07d). Report is 1 commits behind head on development.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## development #376 +/- ## =============================================== + Coverage 93.99% 94.09% +0.09% =============================================== Files 58 59 +1 Lines 2131 2166 +35 =============================================== + Hits 2003 2038 +35 Misses 128 128 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.