By Mike Walters Until Franz Beckenbauer invented the libero’s beat on a football pitch, the only sweepers in town cleaned the streets or chimneys with a brush. But the finest German footballer of them all didn’t just conceive a new position which tacticians have adopted for nearly 60 years without ever matching its innovator’s command of his orbit. When Beckenbauer tidied up at the back, his supreme elegance and majestic calm set him apart from every other player of his craft. In a nation blessed by a 24-carat poacher in the box, Gerd Muller, and Lothar Matthaus threading passes from midfield …