By Diane Bartz and David Shepardson WASHINGTON (Reuters) – The U.S. Justice Department filed a lawsuit against Alphabet’s Google on Tuesday over allegations that the company abused its dominance of the digital advertising business. “Google has used anticompetitive, exclusionary, and unlawful means to eliminate or severely diminish any threat to its dominance over digital advertising technologies,” the government said in its antitrust complaint. The Justice Department asked the court to compel Google to divest its Google Ad manager suite, including its ad exchange AdX. Google said the lawsuit i…