GREEN BAY, Wis. (Reuters) - Republican presidential candidate Donald Trump on Monday will propose a five-year ban on executive branch officials lobbying after they leave government if he is elected, according to excerpts of a speech on fixing ethics problems in Washington. Trump also will say he plans to ask Congress to impose its own five-year ban on former lawmakers and their staff lobbying as well as set a lifetime ban on senior executive branch officials lobbying for foreign governments.  