Function handleNewItemSubmit()
-The input is submitted when the submit is clicked.
  *if input contains text then add to STORE
    else
   if empty input then no action

Function handleItemCheckClicked()
-The Shopping list items are checked upon clicking check button
  *only the closet named list item is checked
  *css, .shopping-item__checked, is selected to display line-through attribute

Function handleDeleteItemClicked()
-The Shopping list items are deleted when delete button is clicked
  *removes the item from STORE