Add Wiki documentation for policies assigned to Security Management Group

[satgurumsss]

As the new ESLZ now reflects a new Security Management group in the Platform landing zone, the documentation does not reflect what policies are being assigned at this MG level, if any.
It would be good to update the documentation here - https://github.com/Azure/Enterprise-Scale/wiki/ALZ-Policies and the corresponding excel sheet link on this page with the new policies for customization purposes and as-built requirements.