A basic menu opens _below_ the anchor element by default. When close to a screen edge, a basic menu vertically realigns to make sure that all menu items are completely visible. The `onClose` callback is called when pressing Esc, Tab, or clicking outside the menu. ### Basic usage
  1. Define a anchorEl to set the position of the menu. The anchor element (ie. button) is NOT part of this component.
  2. Bind open and onClose props.
  3. Use MenuItem as children for default button styling. Set a tabIndex for each item to enable keyboard navigation. Children accepts anything for more customized usage. If MenuItem or button is not the first child element, then apply autoFocus prop on the child element you would like to first focus on when menu is opened.
  4. The menu aligns to the bottom right of the anchorEl by default. This can be customized using the placement prop.