Bis(1-methyl-1H-tetrazol-5-yl)diazene and two its copper(I) chloride complexes poly[[[μ-1,2-bis(1-methyl-1H-tetrazol-5-yl)diazene-κ4N′,N4:N,N4′]dicopper(I)]-di-μ-chloro] and catena-poly[[chlorocopper(I)]-μ-1,2-bis(1-methyl-1H-tetrazol-5-yl)diazene-κ4N′,N4:N,N4′]