[orders] New order taking "tabular" view

New order taking screen dedicated to add products and set quantities across multiple collections within a single screen. Products are displayed across rows and Variants across columns.
The new layout is particularly efficient for one-size products (eg. accessories). Multiple-sizes products will generate one row per product X size.
Quick product add to cart / remove from cart by flying mouse over the product name
Search engine to find products across the catalog

This feature requires the "Advanced order taking" option.