Move nav code out into partial
Add minibasket to navbar

Adds a "minibasket" dropdown to the navbar with item count and basket
price shown on the button. Also assigns an alias to the shopBasket
component used on the payment page to prevent clashes, adds Bootstrap's
fonts that I missed earlier for the button's icon, and finally specifies
a couple more parameters added for the two-components-on-one-page thing.
Fix typo that stopped partial reloading
Update single product page

Removes the duplicate shopBasket component, since this is now set
in the layout instead. Also sets the container element for adding
products to the basket and updating dynamically
Remove redundant checkout page
Merge branch 'feature/basket-dropdown' into develop