User page [3] - Create KPIs and visualisations

[machadoum]

issue

Updating the list of new visualisations:

• Summary of host.os.family
• Summary of agent.type
• Total unique users (like Hosts tab)
• Summary of logon.type
• Total number of alerts grouped by rule name
• Event breakdown, pie chart, donut chart? Event.kind.event (needs design)

[elasticmachine]

Pinging @elastic/security-threat-hunting (Team:Threat Hunting)