code: public static Fairy create(Locale locale, String dataFilePrefix) {
  		return builder().withLocale(locale)
  				.withFilePrefix(dataFilePrefix)
  				.build();
  	}
docs: Use this factory method to create your own dataset overriding bundled one
  
  @param locale         will be used to assess langCode for data file
  @param dataFilePrefix prefix of the data file - final pattern will be jfairy.yml and dataFilePrefix_{langCode}.yml
  @return Fairy instance