[ADD] purchase: Raise warnings on purchase orders

Remove purchase/replenishment/flows/warning_triggering

purchase/purchases/rfq/warning.rst

@@ -0,0 +1,53 @@
+=================================
+Raise warnings on purchase orders
+=================================
+
+The *Warnings* feature allows you to raise warnings or blocking
+messages on purchase orders based on a vendor or a product.
+
+For example, if you often have a problem with a vendor, you might want
+to raise a warning when purchasing from that vendor. If a product is
+about to be discontinued, you may want to raise a blocking message on
+the purchase order.
+
+Configuration
+=============
+
+For this feature to work, go to
+:menuselection:`Purchases --> Configuration --> Settings` and activate
+the *Warnings* feature.
+
+.. image:: media/warning01.png
+    :align: center
+
+Add a warning on a vendor
+=========================
+
+When you activate the feature, you get a new option under the *Internal
+Notes* tab on vendors. You can decide to write a simple warning or a
+blocking message.
+
+.. image:: media/warning02.png
+    :align: center
+
+Add a warning on a product
+==========================
+
+When you activate the feature, you get a new option under the
+*Purchase* tab on the product page where you can add a warning or a
+blocking message.
+
+.. image:: media/warning03.png
+    :align: center
+
+Trying to buy with warnings or blocking messages
+------------------------------------------------
+
+If you try to validate a *Purchase Order* from a vendor or with a
+product with a warning, a message will be raised. You can ignore it by
+clicking ok.
+
+.. image:: media/warning04.png
+    :align: center
+
+However, if it is a blocking message, you can not ignore it.