King Charles has made his first major public appearance since being diagnosed with cancer in February, RadarOnline.com has learned. He and Queen Camilla attended Easter services at Windsor Castle on Sunday, greeting and shaking hands with well-wishers outside St. George’s Chapel. Charles, 75, smiled and joked with members of the public after the service. “You’re very brave to stand out here in the cold,” he told the crowd that had gathered outside the church. When one person told him to “get well soon,” he responded, “I’m doing my best!” “Keep going strong, Your Majesty. Keep going strong, nev…