To quote RM, “I need the whole stadium to jump. Put your phone down, let’s get all the fun.” Or maybe not the whole stadium, but the whole sprawling crowd gathered at Seoul landmark Gwanghwamun, which has been outfitted for the grand return of the groundbreaking K-pop group, BTS. Fresh off the release of their fifth studio album, Arirang, the seven members of BTS — RM, Jin, Suga, J-hope, Jimin, V and Jungkook — kicked off their first group live performance in over three years, BTS The Comeback Live | Arirang, Saturday night in Seoul. The concert special, which was broadcast live around the world on Netflix, had been highly anticipated. Starting with a sweeping shot of Seoul’s Joseon-era Gyeongbokgung Palace, the live-stream eventually revealed the seven men of BTS standing in front of the palace. “Hello, Seoul,” the group’s leader, RM, told the crowd.…