Implement webApi_basket_modify

[spotlightishere]

The route webApi_basket_modify needs to be added.

It appears it POSTs updated attributes. For example, when changing the optionList option and selecting its first (1) value:

    Form item: "action" = "webApi_basket_modify"
    Form item: "platform" = "wii"
    Form item: "authKey" = "ebbddbc1-5540-47ca-b0e1-601d6e5d3b31"
    Form item: "shopCode" = "1"
    Form item: "areaCode" = "08030313630"
    Form item: "basketNo" = "0"
    Form item: "menuCode" = "1"
    Form item: "itemCode" = "1"
    Form item: "option[1][1]" = "1"
    Form item: "quantity" = "1"