src/app/core/ui/navigation/menu-item.ts
        
Structure for menu items to be displayed.
| Properties | 
| icon | 
| icon:          | 
| Type : string | 
| Optional | 
| The icon to be displayed left of the label. | 
| label | 
| label:          | 
| Type : string | 
| The text to be displayed in the menu. | 
| link | 
| link:          | 
| Type : string | 
| Optional | 
| The url fragment to which the item will route to (e.g. '/dashboard') | 
| subMenu | 
| subMenu:          | 
| Type : MenuItem[] | 
| Optional | 
export interface MenuItem {
  /**
   * The text to be displayed in the menu.
   */
  label: string;
  /**
   * The icon to be displayed left of the label.
   */
  icon?: string;
  /**
   * The url fragment to which the item will route to (e.g. '/dashboard')
   */
  link?: string;
  subMenu?: MenuItem[];
}
/**
 * An alternative MenuItem details of an entry in the main navigation.
 */
export interface EntityMenuItem extends MenuItem {
  /**
   * The entity type to whose list this item should link.
   */
  entityType: string;
  subMenu?: (MenuItem | EntityMenuItem)[];
}
/**
 * Object specifying overall navigation menu
 * as stored in the config database
 */
export interface NavigationMenuConfig {
  items: MenuItem[];
}