By Kevin Buckland and Alun John TOKYO (Reuters) – The rouble plunged to an all-time low on Monday, and the dollar soared against nearly all peers after Western nations announced fresh sanctions to punish Russia for its invasion of Ukraine, and Vladimir Putin put nuclear-armed forces on high alert. The rouble dropped to as low as 119 per dollar in early trading, screaming through its previous low of 90 roubles per dollar. The declines came despite Russia’s central bank announcing a slew of steps on Sunday to support domestic markets, after Western allies ratcheted up sanctions including blockin…