Hotels and cruise lines alike are embracing engineered turquoise lagoons for families and travelers.Colorful day beds sit along the lagoon and beach at OKANA Resort & Indoor Waterpark.Credit: OKANA Resort & Indoor WaterparkLast year, just months after Okana Resort & Indoor Waterpark opened in Oklahoma City, waterpark general manager Brian Szydloski fielded an unexpected request: could a couple hold their wedding on the sand of the resort’s artif…