make layout responsive for small devices

[rlueder]

• set search field type to 'tel'
• center placeholder text before ISBN search results
• auto select ISBN on input focus
• make header disappear when scrolling down
• expand/collapse book info so annotations take most of screen space
• style annotation input field/form
• zoom into cover on tap
• add toolbar to jump to book info, annotations, add annotation form
• use icon on Search button
• use React router to navigate through previous searches
• set up PWA