Feature/removing eigen std vector specialization

See: https://eigen.tuxfamily.org/dox/group__TopicStlContainers.html

This header is no longer needed and causes issues in ArmarX packages: EIGEN_STL_VECTOR_SPECIFICATION_DEFINED had to be defined manually.

In Simox, this header won't be used any more. It will be kept for some time such that no code will break. A warning will be printed instead.