Performance improvements for `MultivariatePolynomialFunction` and `PolynomialPathFitter`

[nickbianco]

Fixes issue #3759, #3762. Partially addresses #3761.

Brief summary of changes

This PR implements several performance improvements related to FunctionBasedPath by speeding up function evaluations in MultivariatePolynomialFunction and adding a few new options to PolynomialPathFitter. A brief list of the main changes:

• Added the internal helper class MultivariatePolynomial for computing basic symbolic polynomial function operations.
• Refactored MultivariatePolynomialFunction to compute function values and derivatives based on Horner's scheme.
• Added the method generateDerivativeFunction and generatePartialVelocityFunction to MultivariatePolynomialFunction for conveniently generating moment arm and lengthening speed functions from a muscle path function.
• Added the properties include_moment_arm_functions and include_lengthening_speed_function to PolynomialPathFitter, which leverage the above methods.
• Replaced current least-squares fitting in PolynomialPathFitter with SimTK::FactorQTZ, which should be more robust to poorly conditioned A matrices (this is often the case for the multivariate polynomials since the terms can be highly correlated).
• Fixed the bug described in #3759.

Testing I've completed

Added related tests to testFunctions.cpp and testWrapping.cpp. A summery of the performance benchmarking is below (seeing a ~20-25% speed up).

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CHANGELOG.md (choose one)

• updated.

[perf-win]

Performance analysis

Platform: Windows, self-hosted runner

Test Name	lhs [secs]	stderr [secs]	rhs [secs]	stderr [secs]	Speedup
Arm26	0.36	0.00	0.36	0.00	1.00
Gait2354	0.44	0.00	0.42	0.00	1.03
MocoSlidingMass	1.51	0.00	1.52	0.00	1.00
passive_dynamic	5.63	0.00	5.79	0.00	0.97
passive_dynamic_noanalysis	3.49	0.00	3.48	0.00	1.00
RajagopalModel	9.06	0.00	9.10	0.01	0.99
ToyDropLanding_function_based_paths	15.92	1.35	12.63	0.00	1.26
ToyDropLanding	13.68	0.01	13.72	0.01	1.00
ToyDropLanding_nomuscles	0.57	0.00	0.57	0.00	1.01

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This change is 

[nickbianco]

@pepbos would you be interested in reviewing this? It is related to muscle wrapping and performance.