University of Northern Colorado senior Ashley Driscoll and master’s student Joseph Scardetta will debut compositions spanning themes of revolution, mental health, man vs. machine and, ultimately, stark humanity in UNC Opera Theatre’s “The Opera Garden: Growing New Opera,” 2 p.m. and 7:30 p.m. Saturday, March 25 in Hensel Phelps Theater, UCCC. Driscoll and Scardetta’s compositions …