BOSTON — Harvard University is vowing to spend $100 million to research and atone for its extensive ties with slavery, the school’s president announced Tuesday, with plans to identify and support the descendants of enslaved people who labored at the Ivy League campus. President Lawrence Bacow announced the funding as Harvard released a new report detailing many ways the college benefited from slavery and perpetuated racial inequality. The report, commissioned by Bacow, found that Harvard’s faculty, staff and leaders enslaved more than 70 Black and Native American people from the school’s founding in 1636 to 1783.