[Feature]: Remove Eigen memory alignment management

[jorisv]

🚀 Feature

Pinocchio 4 minimal C++ version will be C++17. Eigen memory alignment management is then no more necessary.

We should:

• Remove EIGEN_MAKE_ALIGNED_OPERATOR_NEW
• Remove use Eigen::aligned_allocator
• Remove internal use of pinocchio::container::aligned_vector, PINOCCHIO_ALIGNED_STD_VECTOR and PINOCCHIO_STD_VECTOR_WITH_EIGEN_ALLOCATOR
• Keep pinocchio::container::aligned_vector alias to maintain a stable API
• Keep PINOCCHIO_ALIGNED_STD_VECTOR and PINOCCHIO_STD_VECTOR_WITH_EIGEN_ALLOCATOR macro to maintain a stable API

Motivation

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Alternatives

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Additional context

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Checklist

• I have checked that there is no similar issue/discussion in the repo.