Resolution of 7,7-dimethylbicyclo[3.2.0]hept-2-en-6-one using Mortierella ramanniana and 3α,20β-hydroxy-steroid dehydrogenase, photochemistry of 3-hydroxy-7,7-dimethylbicyclo[3.2.0]heptan-6-ones, and the synthesis of (+)-eldanolide