product_model auto insert

[michael_s]

Changes :
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1.10 by azer :
- added easier config by define in beginning of file
- now possible to choose between replacing all products_model field or fill only the empty one
- respected the admin the osc layout

To do :
- Count and show number of empty fields
- Write a better confirmation of message at the end
- Show the product processed by the script
- Ask a confirmation showing the number of field that are about to be remplaced or filled

More...