Di-μ-benzoato-di-μ-ethanolato-tetrakis[μ3-5-(hydroxymethyl)-2-methyl-4-(oxidomethyl)pyridin-1-ium-3-olato]tetrakis[μ3-5-(hydroxymethyl)-2-methyl-4-(oxidomethyl)pyridin-3-olato]di-μ3-oxido-heptamanganese(II,III) ethanol octasolvate