[FIX] payment_buckaroo: remove bad link

The link does not work anymore.
Even when it was, it did not provide any information as can be seen in
https://web.archive.org/web/20160608025556/http://www.buckaroo-payments.com:80/business/customers/online-payment/

Fixes #16987

addons/payment_buckaroo/views/payment_views.xml

@@ -11,7 +11,6 @@
                     <group attrs="{'invisible': [('provider', '!=', 'buckaroo')]}">
                         <field name="brq_websitekey"/>
                         <field name="brq_secretkey"/>
-                        <a colspan="2" href="http://www.buckaroo-payments.com/business/customers/online-payment/" target="_blank">How to configure your Buckaroo account?</a>
                     </group>
                 </xpath>
             </field>