[Cisco] [ Documentation] Update Cisco Device integrations docs

Update Cisco Device Integrations like FTD , Meraki , ASA to mention which device classes are supported.

Multiple device classes are sometimes consolidated into integrations and documentation does not reflect all the device class types supported leading to a confusion to the customers.

For various Cisco devices there all integrations including:
[Aironet](https://www.elastic.co/docs/reference/integrations/cisco_aironet)
[ASA](https://www.elastic.co/docs/reference/integrations/cisco_asa)
[Duo](https://www.elastic.co/docs/reference/integrations/cisco_duo)
[FTD](https://www.elastic.co/docs/reference/integrations/cisco_ftd)
[ISE](https://www.elastic.co/docs/reference/integrations/cisco_ise)
[Meraki](https://www.elastic.co/docs/reference/integrations/cisco_meraki)
[Nexus](https://www.elastic.co/docs/reference/integrations/cisco_nexus)
[Secure Email Gateway](https://www.elastic.co/docs/reference/integrations/cisco_secure_email_gateway)
[Secure Endpoint](https://www.elastic.co/docs/reference/integrations/cisco_secure_endpoint)
[Umbrella](https://www.elastic.co/docs/reference/integrations/cisco_umbrella)
[Cisco Meraki Metrics](https://www.elastic.co/docs/reference/integrations/cisco_meraki_metrics)