Replace BroadPhaseMethod enum with shared_ptr<BroadPhase>

[zfergus]

Description

Replace BroadPhaseMethod enum with shared_ptr<BroadPhase>

ToDo:

• Expose BroadPhase to Python inheritance

Type of change

• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• I have followed the project style guide
• My code follows the clang-format style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[codecov]

Codecov Report

Attention: Patch coverage is 90.90909% with 1 line in your changes missing coverage. Please review.

Project coverage is 96.41%. Comparing base (e12c685) to head (f9a2520).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/ipc/broad_phase/hash_grid.hpp	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #152      +/-   ##
==========================================
+ Coverage   96.32%   96.41%   +0.09%     
==========================================
  Files         103      103              
  Lines        7780     7756      -24     
==========================================
- Hits         7494     7478      -16     
+ Misses        286      278       -8     

Flag	Coverage Δ
unittests	96.41% <90.90%> (+0.09%)	⬆️

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