[SIEM] Overview Page - Expand Winlogbeat Stats

[andrewkroh]

The overview page has stats about various data sources. For Winlogbeat I think it would be good to show the number of events Winlogbeat is getting from the Security and Microsoft-Windows-Sysmon/Operational channels.

This query returns those stats:

GET winlogbeat-*/_search
{
  "query": {
    "terms": {
      "winlog.channel": [
        "Microsoft-Windows-Sysmon/Operational",
        "Security"
      ]
    }
  },
  "aggs": {
    "event_count": {
      "terms": {
        "field": "winlog.channel"
      }
    }
  },
  "size": 0
}

[elasticmachine]

Pinging @elastic/siem (Team:SIEM)