Add auto-complete to Search input

[mcarrano]

Optional auto-complete will be added to the Search input component to provide suggestions as the user types. A list of valid suggestions can be supplied by the consumer and can be use case dependent. Unlike for typeahead select, the resulting query string will not be constrained by this list (i.e. the user can enter a value that does not exist in the list). A design spec for this can be found here: https://docs.google.com/document/d/1mFOuhoAJNBSWKHZKwz8T6OVk71OWNPhfAuVF1Jw3BAk/edit?usp=sharing