The German government decided this week to give Judaism the same recognition as an official religion that Protestantism and Catholicism enjoy. The move means Jewish schools and other institutions will qualify for generous government grants. The Jewish community in Germany has grown geometrically since the fall of the U.S.S.R. allowed Soviet Jews to emigrate. From a negligible 30,000 in 1990, it now numbers more than 100,000. This is a historic event, said Paul Spiegel, head of the Central Council of German Jews. That once again Jews live here in considerable numbers is a fact that those who returned after 1945 can hardly imagine.