[+] Project: add the possibility to change the default color (#db3484)

Let the user set the default color in the mail with a color picker (configuration set in Back Office, Themes)
order carrier more compatible with opc

The carriers' block didnt't have the 'opc-main-block' in the order-opc page.
order-carrier more compatible with order-opc

carriers' block didn't have the opc-main-block when in opc-order
order-carrier more compatible with order-opc

carriers' block didn't have the opc-main-block when in opc-order
move header tag out of carrier block
Fixed variable typo (redution instead of reduction in some places)
[-] FO : mobile template - states management
[-] BO : added import button on listing
[*] FO : Cart vouchers style edited
Merge branch 'development' of https://github.com/PrestaShop/PrestaShop into development
// Display exception in admin regardless mode dev
[-] BO : fixed bug #PSCFV-5991 - CMS friendly URL does not automatically copied
[-] BO : fixed bug #PSCFV-6000 - added check if zip uploaded is a real module in AdminModules
[*] FO : Bug fix : h4 -> title_block
Merge branch 'development' of https://github.com/PrestaShop/PrestaShop into development
[-] FO: fix Image attributes not set - #PSCFV-5957
Merge branch 'development' of https://github.com/PrestaShop/PrestaShop into development
[-] Core: Fix search indexation when id_product is forced #PSCFV-6039
//added more check on module upload
//added more check on module upload part 2