Add icons to Input component

[mfmontenegro]

As I've seen on the new design Input component now have the ability to show an Icon.

I would add an optional "icon" prop to the Input component. If it's set, show the Icon.

  const Input: React.FC<IProps> = ({ ... }) => {
    ...
    <Icon isHidden={ !iconName } icon={ icon }>
    ...
  }