Optimize image copy in ShopImport module

2 things :
- copy images to new folder structure instead of legacy one since it's a PS 1.5 branch
- don't create all sizes of images at migration, there's an Admin controller for that (Admin > Settings > Images). That's speed up the import and remove duplicate code (less code to support).

+ some cleaning of unused variables
[-] BO : Display the old image system migration tool if product images are in _PS_PROD_IMG_DIR_
[-] BO : FixBug PSCFV-10331 - Tax rules Pagination
[-] MO: Fix unifunc smarty errors if module is displayed on multiplehook without cache
// revert form https://github.com/PrestaShop/PrestaShop/commit/2874f1498352228c84df969c42e9d8f699a8afc5
Add some fields to Orders in Import module
Merge pull request #706 from sjousse/development

[*] MO : Add some fields to Orders in Import module
Merge pull request #699 from sjousse/patch-1

[*] MO : ShopImporter Optimize image copy in ShopImport module
fix imported prices
Merge pull request #707 from sjousse/development

[-] MO: ShopImporter fix imported prices
[-] IN : Remove notice when upgrading from
[-] FO: Fix SSL links on domain_ssl instead domain
[*] MO : MailAlerts : multishop/multilang full compatibility
Customers will receive alerts based on the real context of the moment they subscribed to the alert (sho, theme & language)

SQL update table : `ps_mailalert_customer_oos`
=========================================

ALTER TABLE `ps_mailalert_customer_oos`
ADD `id_lang` INT( 10 ) UNSIGNED NOT NULL ,
DROP PRIMARY KEY ,
ADD PRIMARY KEY ( `id_customer` , `customer_email` , `id_product` , `id_product_attribute` , `id_shop` ) ;
// small fix for image SSL links
[*] MO : MailAlerts : Add SQL update script for v2.5
[-] MO : Statsdata, exception on duplicate entry
[-] MO : carriercompare fixed bug, override template's files in theme. Ticket #PNM-1691
Add Bcc support in Mail class
Merge pull request #710 from nilsga/development

[*] CORE : Add Bcc support in Mail class
[-] FO : Fix bug #PSCFV-8917 taxes calculation when changing delivery address