Isotropic and Anisotropic Magnetic Exchange Interactions through .mu.-N1,N2 1,2,4-Triazole and .mu.-Sulfato Bridges: X-ray Crystal Structure, Magnetic Properties, and Single-Crystal EPR Study of (.mu.-4-Amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole-N',N1,N2,N'')(.mu.-sulfato-O,O')[(sulfato-O)aquacopper(II)]triaquacopper(II) Hydrate