docs: matter: Derived Matter Product guide

Creates guideline to leverage the Matter complaint platform
to fasten product certification.

Signed-off-by: Michał Szablowski <[email protected]>

Author: doublemis1

doc/nrf/protocols/matter/end_product/index.rst

@@ -26,6 +26,7 @@ Also, topics related to Matter certification (:ref:`ug_matter_device_attestation
    :caption: Subpages:
 
    prerequisites
+   platform_dmp_cert
    factory_provisioning
    attestation
    dcl