Structures and Spectral Properties of Some Bis(β-diketonato)copper(II)–Diazole Complexes. II. The 1:1,1:2, and 1:3 Adducts of Bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)copper(II) and 4-Methyl-1H-pyrazole