After more than seven years leading the influential Massachusetts Taxpayers Foundation, Eileen McAnneny on Wednesday announced her plans to step down at the end of 2022. “This has been a phenomenal job,” said McAnneny, who relayed her decision at the business-backed group’s annual meeting. “[But] a job like this, at least for me, is all consuming. I think a lot of people, since the pandemic, are reevaluating life. I certainly went through a little of that.”