These traits are akin to the deprecated standard library traits (Zero, One,
Primitive) to keep everything running as before. However, for the long term a
better algebraic abstraction should be used/provided.
Moved the old source code temporarily to src-old. This will be removed once the functionality has been transferred over into the new system.
The new design is based on algebraic principles. Thanks goes to sebcrozet and his nalgebra library for providing the inspiration for the algebraic traits: https://github.com/sebcrozet/nalgebra
