Add autocomplete functionality to search-input and search-box

The search box that is commonly in the header of a site and the search input on a search page often require some form of autocomplete, this should be supported out of the box by the search-box and search-input components.

To Do

• Determine if we should use https://www.drupal.org/project/search_api_autocomplete → or something from search api itself
• Identify config options for the components
• Determine expected behaviors/interactions
• Identify a sensible html structure
• Identify accessible implementation approach for html and interactions