Who is young Mercedes star Andrea Kimi Antonelli?

Andrea Kimi Antonelli has been the talk of the Formula 1 world for months now. The young Italian is a member of the Mercedes Junior Team, and his arrival in Formula 1 appears imminent. Rumours surrounding Antonelli suggest he could be a Mercedes driver as early as next year. Who is the 17-year-old, how has he risen up the ranks so quickly, and what are his F1 options?