More than 20 years ago, Kronos Quartet’s David Harrington heard Azerbaijan’s great singer Alim Qasimov perform mugham — Azeri poetry as song — for the first time. Meanwhile, Qasimov had a dream. He’d seen Turkish and Iranian groups play with cellos and violins. “I can only imagine,” he told the Aga Khan Trust, “what you could do with our mugham if you had those instruments.” He needed the help of an arranger, without whom such a large ensemble performance would be impossible. That’s where Harrington and Kronos stepped in. They enlisted Jacob Garchik to make Qasimov’s dream a reality, which they brought to the University of Maryland on Saturday night.