Washington (AFP) – A sprawling conspiracy, a cornered president clinging to power, a White House cover-up: for Watergate prosecutor Jill Wine-Banks, the mushrooming controversy around Donald Trump’s alleged plot to take down US democracy is a movie she’s seen before. It is 50 years to the day since five burglars were arrested at the Democratic National Committee headquarters at the Watergate complex in Washington — touching off a firestorm that would bring down president Richard Nixon. The break-in plunged Wine-Banks — barely out of her 20s — into a starring role in the most enduring politi…