title: UWP get country phone number prefix
body: <p>I want to get the country prefix for phone numbers.</p>
  
  <p>e.g. if I am in the US and I enter the number <code>0123 - 456</code>, I want to get the prefix <code>+1</code> or <code>001</code>, so the number in the end is <code>(+1) 0123 - 456</code>
  If I am in Germany the same phone number would be <code>(+49) 0123 - 456</code>.</p>
  
  <p>How can I do this in a UWP app? I can't find anything in the globalization or cultureinfo namespace. </p>