Add FreeListAllocator class

[jslee02]

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Before creating a pull request

• Document new methods and classes
• Format new code files using ClangFormat by running make format
• Build with -DDART_TREAT_WARNINGS_AS_ERRORS=ON and resolve all the compile warnings

Before merging a pull request

• Set version target by selecting a milestone on the right side
• Summarize this change in CHANGELOG.md
• Add unit test(s) for this change

[codecov]

Codecov Report

Merging #1639 (e15c6ba) into main (8eb7688) will increase coverage by 0.09%.
The diff coverage is 80.20%.

❗ Current head e15c6ba differs from pull request most recent head fa78bc3. Consider uploading reports for the commit fa78bc3 to get more accurate results

@@            Coverage Diff             @@
##             main    #1639      +/-   ##
==========================================
+ Coverage   58.96%   59.05%   +0.09%     
==========================================
  Files         485      488       +3     
  Lines       40272    40432     +160     
==========================================
+ Hits        23746    23878     +132     
- Misses      16526    16554      +28     

Impacted Files	Coverage Δ
dart/common/CAllocator.hpp	100.00% <ø> (ø)
dart/common/FreeListAllocator.hpp	0.00% <0.00%> (ø)
dart/common/StlAllocator.hpp	100.00% <ø> (ø)
dart/common/StlHelpers.hpp	80.00% <ø> (ø)
dart/common/detail/Aspect.hpp	78.57% <ø> (ø)
dart/common/detail/Castable-impl.hpp	100.00% <ø> (ø)
dart/lcpsolver/ODELCPSolver.cpp	0.00% <ø> (ø)
dart/optimizer/ipopt/IpoptSolver.cpp	73.18% <ø> (ø)
dart/common/CAllocator.cpp	71.11% <79.16%> (ø)
dart/common/FreeListAllocator.cpp	80.00% <80.00%> (ø)
... and 6 more