By George Obulutsa and Ayenat Mersie NAIROBI (Reuters) -William Ruto was sworn in as Kenya’s fifth president on Tuesday, a week after the Supreme Court rejected a challenge by his defeated opponent in a close-fought election he won by portraying himself as an underdog “hustler” battling the elite. Deputy president for the last decade, Ruto must now confront an economic crisis in East Africa’s wealthiest and most stable nation, where food and fuel prices are surging, unemployment is high and public debt rising. “A village boy has become the president of Kenya,” Ruto said at the ceremony, as the…