DUBAI — Cryptocurrency firm Tether plans to move its headquarters to El Salvador, its chief executive said, as the founders of the world’s biggest stablecoin look to capitalize on the Central American country’s bid to become a hub for crypto trading. Tether has emerged as a dominant force in the booming market for stablecoins, which are designed to maintain a constant value by being pegged to traditional currencies and offer users a way to move money between cryptocurrencies without exposure to price swings. CEO Paolo Ardoino told Reuters that Tether would relocate to El Salvador after the cryptocurrency recently obtained