Leonard's Bakery   What more can be said about this institution? Founded by Frank Leonard Rego in 1952, and still operated by the Rego family, the bakery began making Portuguese confections the following year, at the suggestion of Margaret Rego. They were the first, the malasadas were a hit, and the rest is grease-stained history. A must-stop for visitors. Pick up some pao doce (rich egg bread) while you're there.  933 Kapahulu Ave. 737-5591. 6 a.m.-9 p.m. Sundays-Thursdays; 6 a.m.-10 p.m. Fridays and Saturdays. AX, DC, DS, JCB, MC, VS. Checks accepted. $.