code: public static String externalUrl(final IRI identifier, final String baseUrl) {
          if (baseUrl.endsWith("/")) {
              return replaceOnce(identifier.getIRIString(), TRELLIS_DATA_PREFIX, baseUrl);
          }
          return replaceOnce(identifier.getIRIString(), TRELLIS_DATA_PREFIX, baseUrl + "/");
      }
docs: Generate an external URL for the given location and baseURL.
  
  @param identifier the resource identifier
  @param baseUrl the baseURL
  @return the external URL