Feature/MiniBag

[owensmooth]

related issue: https://github.com/shiftcommerce/shift-front-end-react/issues/373

Implements MiniBag component.
The basket icon was originally in that component but has been moved to layout.

• Minibag pops up when you add an item to basket, this waits for the cart action to come back successful before popping up.
• When you click the basket it renders the minibag, closes when you click the cross.

MiniBag

Add to basket

[hubertpompecki]

Looks good, but, as discussed, I think we should also have it so that clicking anywhere outside of the minibag causes the minibag to close.