feat: Add `shopping-cart` icon

Closes #20, closes #79, closes #159

icons/shopping-cart.svg

+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><circle cx="8" cy="21" r="2" fill="none" stroke="#000" stroke-linecap="round" stroke-linejoin="round" stroke-width="2"/><circle cx="20" cy="21" r="2" fill="none" stroke="#000" stroke-linecap="round" stroke-linejoin="round" stroke-width="2"/><path d="M5.67,6H23l-1.68,8.39a2,2,0,0,1-2,1.61H8.75a2,2,0,0,1-2-1.74L5.23,2.74A2,2,0,0,0,3.25,1H1" fill="none" stroke="#000" stroke-linecap="round" stroke-linejoin="round" stroke-width="2"/></svg>
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