ST PETERSBURG, Russia (Reuters) -President Vladimir Putin on Sunday signed a new naval doctrine which cast the United States as Russia’s main rival and set out Russia’s global maritime ambitions for crucial areas such as the Arctic and in the Black Sea. Speaking on Russia’s Navy Day in the former imperial capital of St Petersburg founded by Tsar Peter the Great, Putin praised Peter for making Russia a great sea power and increasing the global standing of the Russian state. After inspecting the navy, Putin made a short speech in which he promised that what he touted as Russia’s unique Zircon hy…