Added a Template for a letter for automatic registration of users when ordering.

Added a Template for a letter for automatic registration of users when ordering. You can change the template in the section "E-mail newsletters", "Letter templates".

Added extended Google Merchant XML upload for advertising in Google Merchant and Facebook, with product characteristics.
Added the ability to limit the addition of goods to the basket, by its quantity in stock.
Added Widget for simplified footer management (bottom block)