Create function that help you add element to sorted list

[ikfir]

Should be called addElementSorted The function should take List<E> E Comparator<E>

Example of usage

        List<Integer> list = new ArrayList<>();
        Comparator<Integer> comparator = Integer::compare;

        CollectionHelpers.addElementSorted(list, 1, comparator);
        CollectionHelpers.addElementSorted(list, 7, comparator);
        CollectionHelpers.addElementSorted(list, 9, comparator);
        CollectionHelpers.addElementSorted(list, 2, comparator);

        // List [1, 2, 7, 9]

[ikfir]

Closed by #77 where I added it