By Dan Marsh Former Manchester United interim manager Ralf Rangnick has emerged as a surprise contender to succeed Xavi Hernandez at Barcelona next season. Rangnick, 65, has a rich coaching pedigree and is revered in his native Germany but endured a disastrous spell at Old Trafford after agreeing to step in on a temporary following Ole Gunnar Solskjaer’s sacking back in November 2021. The former RB Leipzig coach has been in charge of the Austria national team since leaving United and successfully guided them to qualification for next summer’s European Championships \- a feat that has seemingly…