[ task #176 ] Allow to use ODT templates. Works with Orders

htdocs/admin/commande.php

...re/modules/commande/doc/doc_generic_order_odt.modules.php

htdocs/core/modules/commande/doc/pdf_edison.modules.php

htdocs/core/modules/commande/doc/pdf_einstein.modules.php

htdocs/core/modules/commande/modules_commande.php

htdocs/core/modules/modCommande.class.php

htdocs/install/doctemplates/orders/template_order.odt