WASHINGTON — Oath Keepers founder Stewart Rhodes was convicted Tuesday of seditious conspiracy for a violent plot to overturn Democrat Joe Biden’s presidential win, handing the Justice Department a major victory in its massive prosecution of the Jan. 6, 2021, insurrection.A Washington, D.C., jury found Rhodes guilty of sedition after three days of deliberations in the nearly two-month-long trial that showcased the far-right extremist group’s efforts to keep Republican Donald Trump in the White House at …