Links (#615)

* add URL support to Label element and XML parsing

* refactor Label URL handling to use getter method in setURL

* implement URL opening confirmation dialog and platform-specific URL handling

* fix: fixed build errors

* remove: delete test link label from worlds.xml

* refactor: remove URL handling from Label class and XML parsing

* refactor: clean up Label class by removing unnecessary whitespace and improving code readability

* refactor: remove unused URL member from Label class

* refactor: remove unused URL attribute from XML UI documentation and related code

* refactor: improve code readability by adding whitespace and formatting adjustments in Label class

* refactor: improve whitespace consistency in Label class and add URL opening functionality in libcore

res/texts/ru_RU.txt

@@ -25,6 +25,7 @@ Grant %{0} pack modification permission?=Выдать разрешение на
 Error at line %{0}=Ошибка на строке %{0}
 Run=Запустить
 Filter=Фильтр
+Are you sure you want to open the link: =Вы уверены, что хотите открыть ссылку: 
 
 editor.info.tooltip=CTRL+S - Сохранить\nCTRL+R - Запустить\nCTRL+Z - Отменить\nCTRL+Y - Повторить
 devtools.traceback=Стек вызовов (от последнего)