The top executive at embattled plane maker Boeing will step down this year amid a broader shakeup of the company’s top leadership, capping a tumultuous five-plus years that has shaken faith in one of the US’s most storied manufacturers. The company has come under intense scrutiny over its manufacturing process since a pair of its marquee aircraft crashed, killing hundreds of people in late 2018 and 2019 in Indonesia and Ethiopia. Those problems have snowballed and the Federal Aviation Administration recently ordered an audit of assembly lines at a Boeing factory near Seattle, where the company…