#21: 💪 Enrich the todo-item component

So... We're still working on this one, but the purpose here is to be able to edit your todo item and use the input-button-unit component for this. You can either add an edit button or just let the user click or double click on the item's title. Then the simple item can be replaced (with *ngIf) with the reusable component. You should pass the title as an input and catch the submit event to update the title.