After five years of legal battles, gentrification concerns and a federal review, Barack and Michelle Obama were expected to attend a celebratory groundbreaking Tuesday on their legacy project in Chicago’s lakefront Jackson Park.Construction on the site along Lake Michigan, near the Obama family home and where the former president started his political career on Chicago’s South Side, officially began last month. Work on the Obama Presidential Center is expected to take about five years.The Obamas were scheduled to host an …