45 parallelize point est hist and naive stack

[joselotl]

Problem & Solution Description (including issue #)

This PR parallelizes naive stack. It modifies some of the logic from input_iterator and adds functions to data.py in order to be able to use the iterator to qp ensambles.

Code Quality

• My code follows the code style of this project
• I have written unit tests or justified all instances of #pragma: no cover; in the case of a bugfix, a new test that breaks as a result of the bug has been added
• My code contains relevant comments and necessary documentation for future maintainers; the change is reflected in applicable demos/tutorials (with output cleared!) and added/updated docstrings use the NumPy docstring format
• Any breaking changes, described above, are accompanied by backwards compatibility and deprecation warnings

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (da3a845) 97.13% compared to head (0f62392) 96.95%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #64      +/-   ##
==========================================
- Coverage   97.13%   96.95%   -0.18%     
==========================================
  Files          32       32              
  Lines        1675     1709      +34     
==========================================
+ Hits         1627     1657      +30     
- Misses         48       52       +4     

Files	Coverage Δ
src/rail/core/stage.py	99.14% <100.00%> (+0.03%)	⬆️
src/rail/core/data.py	99.23% <88.88%> (-0.37%)	⬇️
src/rail/estimation/algos/naive_stack.py	94.73% <90.62%> (-5.27%)	⬇️

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[eacharles]

Looks good. We need to figure out how to test his under MPI with the new pyproject.toml / github actions, but that is a different question