By Jillian Dara It’s not often that you find “serenity,” “coastal living” and “New York City” in the same sentence, but an Australian pearling family is seeking to change that with Wall Street’s newest luxury hotel. Aptly named The Wall Street Hotel for its locale, set between Water and Pearl Streets, the newly opened 180-room hotel introduces a new style to the traditionally chaotic, boisterous bustle of downtown — one that’s softer, subtler and exponentially more spacious. With five room categories, guest accommodations start at 280-square-feet for a king range and size up to a 700-square-fo…