Michael Schneider Variety Editor at LargeIn his 2014 memoir “Even This I Get to Experience,” TV legend Norman Lear writes about the busiest period of his life as a time of “joyful stress.”The 1970s were the pinnacle of Lear’s success as an uber producer, and at one point he simultaneously had eight shows on the air — including such landmark sitcoms as “All in the Family,” “One Day at a Time,” “Sanford and Son,” “Good Times,” “Maude,” “The Jeffersons” and “Mary Hartman, Mary Hartman.”“Even doing