[IMP] (website_)sale: Prevent users to create sales orders from invoicing menuitems

Purpose
=======

The menu "Sales -> Invoicing -> Orders to invoice , shows the orders which are confirmed and where the invoice needs to be created for those.
User should not be able to create SO from this menu.

===========
Specification
===========

Remove create Button in (Order to invoice and Order to upsell) menu  and in website -> order to invoice

addons/sale/models/sale.py

@@ -82,6 +82,12 @@ class SaleOrder(models.Model):
                 'invoice_status': invoice_status
             })
 
+    @api.model
+    def get_empty_list_help(self, help):
+        if help:
+            return '<p class=''oe_view_nocontent_create''">%s</p>' % (help)
+        return super(SaleOrder, self).get_empty_list_help(help)
+
     @api.model
     def _default_note(self):
         return self.env.user.company_id.sale_note

addons/sale/views/sale_views.xml

@@ -481,7 +481,7 @@
             <field name="res_model">sale.order</field>
             <field name="view_type">form</field>
             <field name="view_mode">tree,form,calendar,graph,pivot,kanban</field>
-            <field name="context">{}</field>
+            <field name="context">{'create': False}</field>
             <field name="domain">[('invoice_status','=','to invoice')]</field>
             <field name="search_view_id" ref="view_sales_order_filter"/>
             <field name="help" type="html">
@@ -507,7 +507,7 @@
             <field name="view_type">form</field>
             <field name="view_mode">tree,form,calendar,graph,pivot,kanban</field>
             <field name="domain">[('invoice_status','=','upselling')]</field>
-            <field name="context">{}</field>
+            <field name="context">{'create': False}</field>
             <field name="search_view_id" ref="view_sales_order_filter"/>
             <field name="help" type="html">
               <p>

addons/website_sale/views/sale_order_views.xml

@@ -62,7 +62,7 @@
         <field name="res_model">sale.order</field>
         <field name="view_mode">tree,form</field>
         <field name="domain">[('state', 'in', ('sale', 'done')), ('invoice_status', '=', 'to invoice')]</field>
-        <field name="context">{'show_sale': True, 'search_default_from_website': 1}</field>
+        <field name="context">{'show_sale': True, 'search_default_from_website': 1, 'create': False}</field>
         <field name="search_view_id" ref="view_sales_order_filter_ecommerce"/>
         <field name="help">You don't have any order from the website.</field>
     </record>