[ADD] Add button to update a product's financings after changing lst_price field

It will add a button called 'Update financings' on product form view to update financing quota_amount based on lst_price. It will also warn the user to use the button after changing the lst_price value.

data/cron_data.xml

+<?xml version="1.0" encoding="UTF-8"?>
+
+<openerp>
+
+    <data>
+        <record forcecreate="True" id="ir_cron_sync_invoices" model="ir.cron">
+            <field name="name">Invoice Credipaz synchronization</field>
+            <field eval="True" name="active" />
+            <field name="user_id" ref="base.user_root" />
+            <field name="interval_number">1</field>
+            <field name="interval_type">hours</field>
+            <field name="numbercall">-1</field>
+            <field eval="True" name="doall" />
+            <field eval="'account.invoice'" name="model" />
+            <field eval="'cron_try_sync_invoices'" name="function" />
+        </record>
+
+    </data>
+</openerp>