LIST SUPERUSERS cql command

Developing a new CQL command LIST SUPERUSERS to return list of roles with superuser privilege. This includes roles who acquired superuser privilege in the hierarchy. 

Context: LIST ROLES cql command lists roles, their membership details and displays super=true for immediate superusers. But there can be roles who acquired superuser privilege due to a grant. LIST ROLES command won't display super=true for such roles and the only way to recognize such roles is to look for atleast one row with super=true in the output of LIST ROLES OF <role name> command. While this works to check is a given role has superuser privilege, there may be services (for example, Sidecar) working with C* and may need to maintain list of roles with superuser privilege. There is no existing command/tool to retrieve such roles details. Hence developing this command which returns all roles having superuser privilege.