erp5_xhtml_style: define how any page in ERP5 should be printed by removing bars

When printing an ERP5 page (through the print function of the web browser itself), remove :
- toolbars
- tabs
This allows to print any ERP5 page, reports rendered as html included

product/ERP5/bootstrap/erp5_xhtml_style/SkinTemplateItem/portal_skins/erp5_xhtml_style/erp5.css.xml

@@ -1437,6 +1437,22 @@ div.pdf-preview-navigation img.last{\n
 .captchas_dot_net {\n
     border: none; \n
     vertical-align: bottom\n
+}\n
+\n
+@media print {\n
+\n
+  .bars {\n
+    display: none;\n
+  }\n
+  \n
+  .status {\n
+    display: none;\n
+  }\n
+  \n
+  .actions {\n
+    display: none;\n
+  }\n
+\n
 }
 
 ]]></string> </value>