[WIP] Get site_packages path with pybind11 API in C++ backend

[multiphaseCFD]

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[SC-53754] Context:

Description of the Change:

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[github-actions[bot]]

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[codecov[bot]]

Codecov Report

Attention: Patch coverage is 97.33333% with 2 lines in your changes missing coverage. Please review.

Project coverage is 95.06%. Comparing base (83ac9d8) to head (77a8b21).

Files	Patch %	Lines
..._lightning/core/src/utils/BLASLibLoaderManager.hpp	95.91%	2 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #701      +/-   ##
==========================================
- Coverage   95.11%   95.06%   -0.06%     
==========================================
  Files         113       74      -39     
  Lines       18153    11524    -6629     
==========================================
- Hits        17267    10955    -6312     
+ Misses        886      569     -317     

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[multiphaseCFD]

Home/.local/ libs are missing when I tested catalyst against PR#701, which leads to the failures in Catalyst tests. I found that this is an issue created in the pybind11 repo here.