When Rangers signed Dujon Sterling on a free transfer from Chelsea last summer, the Scottish Premiership giants appeared to have snapped up a right-back to provide competition for captain James Tavernier. What The Gers fans probably didn’t expect, however, was that the former Stoke City loanee would also be a fine addition to Philippe Clement’s midfield, slotting into a central role when required while never looking out of place even for a second. Sterling has thrived as a buccaneering right-winger too and, against Celtic in Sunday’s 3-3 Old Firm derby thriller, added yet another string to his…