The alleged gunmen in a shooting rampage that left three people dead outside a San Diego mosque have been identified as 17-year-old Cain Clark and 18-year-old Caleb Velasquez, according to a law enforcement source. At least one of the suspects took a weapon from his parents’ home and left a suicide note that talked about racial pride, a law enforcement source told The Post. Clark attended Madison High School and was a standout wrestler, according to the school’s social media page. His grandfather, David Clark, 78, said: ”We’re very sorry for what happened. We know as much as you do....