Product page styling

[larkinds]

This pull request addresses #82, styling the Single Product Page. In addition, it creates the single product page and sets up routing from the homepage to the single product page. Note that it does not create routing from the hall of fame, as each icecream in that page includes an 'add to cart' button.

This request also has some clean up and some accessibility work included.

• [x] Creates a single product page
• [x] Sets up routing to that single product page
• [x] Styles the singe product page
• [x] Makes the single product page fully responsive
• [x] Check for keyboard accessibility