Cosy is not the word that would normally spring to mind when discussing a prehistoric mound — especially one that contained ancient human remains . . . and some (regrettably) newer ones. But the Neolithic burial site known as Newgrange in the midst of the bucolic Irish countryside feels safe . . . comforting even.   Set on a grassy hilltop near a bend in the River Boyne, the oval-shaped structure softly rises above the rolling farmland dotted with sheep, cows and yellow fields of canola. Access to the site is controlled by the Brú na Bóinne Visitor Centre and the cost of a vistor’s pass starts at €2.   As the Irish will proudly tell you, this structure is older than the Great Pyramids and Stonehenge.…