locations: Add Ulsan city and Ulsan Airport
Add Ulsan, a metropolitan city in South Korea with a population of over 1.1 million.
Coordinate data for Ulsan is that of Ulsan City Hall, from OpenStreetMap.
Also, add Ulsan Airport (RKPU) which is a METAR station as indicated by https://www.aviationweather.gov/docs/metar/stations.txt.
Coordinate data for Ulsan Airport is from officially published data by the Korea Airports Corporation (한국공항공사).
Edited by Bryan Kim