SEOUL (Reuters) - Samsung Electronics' board Chairman Lee Sang-hoon, who was convicted and jailed for sabotaging union activities, has resigned from the South Korean company, it said on Friday.The resignation comes less than two years after Lee's appointment split the chairman and chief executive roles for the first time in an effort to enhance transparency and independence of the world's top memory chip manufacturer in the wake of a corruption scandal involving group heir Jay Y. Lee."Samsung..