Portugal’s former prime minister António Costa is tipped to be named the next President of the European Council, in a move that could see him fully restore his political credibility after he was embroiled in a corruption investigation that brought his stay in office to a halt. After lengthy discussions in Brussels on Monday, EU diplomats said Costa is one of a trio of candidates pencilled in for three power roles in Brussels, although the appointments are still vulnerable to political horse-trading. His status as a testemunha (witness) in an ongoing judicial probe into corruption and influence…