Peter Corroon became emotional as he recalled the long journey that led him to the lobby of a new affordable housing complex where he stood. Corroon, the former Salt Lake County mayor and the project’s final developer, signed on in 2017 to become a minority partner of what was supposed to be a market-rate apartment development in Central City. Initial planning started at least two years before that, but it had already gone through many hurdles, and there were many yet to come.