Preparation and Crystal Structure of the trans(O5) Isomer of Magnesium(ethylenediamine-N,N,N′-triacetato-N′-3-propionato)cuprate(II) Octahydrate, Mg[Cu(ed3ap)]·8H2O. Stereochemistry of Octahedral Cu(II)-EDTA-Type Complexes in Relation to the Structure of the Ligand