[New Integration] Cisco Catalyst Center (DNA Center)

This feature request proposes adding support for monitoring and categorizing metrics collected from the Cisco Catalyst Center.

- overall health
- sites
- device
- interface
- client

Start with issue #13787 and determine the repository entry points for a new integration; the issue names no files, tests, or existing implementation. Clarify how Cisco Catalyst Center should expose overall health, sites, devices, interfaces, and clients, then define validation and completion criteria for each metric category.

Written by the indexing model from the issue text.