“I had one of the best jobs in the world,” said Chris Sacca, who left Google. “But there is a world of opportunity.”Credit...Librado Romero/The New York Times SAN FRANCISCO � Chris Sacca had a plum job as the Wi-Fi guru at Google. But with his stock options fully vested, he left the Internet search company this month for a new career as a venture capitalist. Mr. Sacca, 32, joins a growing number o