GSF Material effects : Use value rahter than ptr, use ATH_MSG , cleanup

• use std::vector<AmgSymMatrix(5),Eigen::aligned_allocator<AmgSymMatrix(5)> > deltaCovariances;instead of std::vector<std::unique_ptr<const AmgSymMatrix(5)>> deltaCovariances; .
• The special allocator sees to be needed from here https://eigen.tuxfamily.org/dox/group__TopicStlContainers.html. This allows to avoid a few allocations.
• Use ATH_MSG_rather than msg(MSG::...) <<
• Use emplace_backfor the ComponentValues for the BetheHeitler effects .