President Donald Trump's hotel management company, New York City-based Trump Hotels, plans to put a stake in the ground in downtown Dallas with a new hotel — which could be the first concept of its kind realized in the United States. The Dallas Business Journal has learned the hotelier plans to place its new 4-star concept, called Scion, within walking distance to Dallas' city hall. Trump Hotels' new Scion Dallas hotel — a six-story, 220-room hotel with ground-floor retail space — will sit…