FEATURE: Add dashboard for NetFlow

[dougburks]

As a defender, I'd like a dashboard specific to NetFlow records:

event.module:netflow | groupby source.ip | groupby -sankey source.ip destination.ip | groupby destination.ip | groupby destination.port | groupby network.type | groupby network.transport | groupby network.direction | groupby netflow.type | groupby netflow.exporter.version  | groupby observer.ip | groupby source.as.organization.name | groupby source.geo.country_name | groupby destination.as.organization.name | groupby destination.geo.country_name

    ':netflow:':
        - soc_timestamp
        - event.dataset
        - source.ip
        - source.port
        - destination.ip
        - destination.port
        - network.type
        - network.transport
        - network.direction
        - netflow.type
        - netflow.exporter.version
        - observer.ip

[dougburks]

Tested and verified: