[SIEM] Additional Overview Network & Hosts metrics

[stephmilovic]

Summary

Adds new network and host metrics to the SIEM overview page as per https://github.com/elastic/ingest-dev/issues/502

This is a lot of gql boilerplate. The file that matters most for code review is the query dsl: x-pack/plugins/siem/server/lib/overview/query.dsl.ts

[NOTE]: I am still wrestling to get data into my esarchiver tests, please ignore the 0's for now.
[OTHER NOTE]: Palo Alto and Cisco data is not on the siem-dev cluster, so ignore those 0's as well

Checklist

Use strikethroughs to remove checklist items you don't feel are applicable to this PR.

• This was checked for cross-browser compatibility, including a check against IE11
• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Documentation was added for features that require explanation or tutorials
• Unit or functional tests were updated or added to match the most common scenarios
• This was checked for keyboard-only and screenreader accessibility

For maintainers

• This was checked for breaking API changes and was labeled appropriately
• This includes a feature addition or change that requires a release note and was labeled appropriately

[elasticmachine]

Pinging @elastic/secops

[angorayc]

Thanks @stephmilovic , checked out and viewed with chrome, firefox, safari, and IE11, all looks fine. Good to merge once build success.

[stephmilovic]

jenkins retest this

[elasticmachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request