This creates a menu item using Semantic UI
menu_item(..., item_feature = "", style = NULL, href = NULL)
Content of the menu item: text, icons or labels to be displayed.
If required, add additional item feature like 'active', 'header', etc.
Style of the item, e.g. "text-align: center".
If NULL (default) menu_item is created with 'div' tag. Otherwise it is created with 'a' tag, and parameeter defines its href attribute.