Sovereign immunity — Foreign governments and their officials — Government of political subdivision of foreign State — Province of Newfoundland — Alleged violation by Province and its officials of United States securities laws — Whether officials entitled to immunity — Whether Province entitled to immunity — Role of the United States Department of State — Conclusiveness of suggestion of immunity by Department of State — Whether United States Securities Exchanage Act 1934 applies to foreign governments — Service of process — The law of the United States