Create pledge module for Prestashop 1.6

Dear Freelancers, we need to integrate the german can and bottle pledge / deposit in Prestashop 1.6. (actually 1.6.0.11). Therefore we need a way to configure the pledge / deposit in the backend. It should be possible to create new ones and change the value from existing. At the moment we need for returnable bottles 0,08 Euro and for returnable cans 0,25 Euro. Only value is needed. Furthermore, the product details in the backend need to be extended by a pledge-selector. This means that we have to be able to assign a specific pledge (either 0,08€ or 0,25€ or..) to one product. Best place is „Catalog“ → „Products“ → tab „Prices“. On the product-detail-site {$pledge} must be possible, it's the value of the pledge for the product. We have to show it near by the price, like „Price incl. VAT, plus {$pledge} € pledge and shipping. The prices must NOT add up right away. There should only be one line above the tax, indicating which pledge applies. Example: 1 Can Coke: 0,69€ + 0,25€ pledge The pledge will be added to the total in the shopping cart. Therefore the pledge will be counted as a product on the bill. Various pledges could either add up (=one product one the bill) or appear as they are (=many small values). Example 1 Can Coke: 0,69€ 1 pledge 0,25€ 1 Can Pepsi 0,69€ 1 pledge 0,25€ ___________________ = 1,88 € total sum The total sum includes VAT 0,30 Euro. (at for example 19%) OR----------- 1 Can Coke: 0,69€ 1 Can Pepsi 0,69€ 2 pledge 0,50€ ___________________ = 1,88 € total sum The total sum includes VAT 0,30 Euro. (at for example 19%) The VAT percentage it's the same as the VAT percentage from the product, it can be the normal VAT percentage (actually 19% in Germany) or the foodstaff VAT percentage (actually 7% in Germany). This must be taken into account when calculating the tax included.