User/host details flyouts + Asset criticality

[natasha-moore-elastic]

Contributes to the following issues:

• [Request]: Create docs for new user details flyout UI #4459 and [Request]: Create docs for new host details flyout UI #4576 by documenting the new expandable user and host details flyouts
• [Request] Update information on how risk score is calculated to include asset criticality #4697 by updating the information on how risk score is calculated
• [Request] Document Asset Classification capability and how it impacts Entity risk scoring #4841 by documenting the asset criticality feature

Twin serverless PR: https://github.com/elastic/staging-serverless-security-docs/pull/280

Previews:

New page:

• Asset criticality

Updated pages:

• View and analyze risk score data
• Entity risk scoring
• Turn on the risk scoring engine
• Manage detection alerts
• Hosts page
• Users page
• Configure advanced settings
• Entity risk scoring prerequisites - has ESS-specific updates

[github-actions]

A documentation preview will be available soon.

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[joepeeples]

LGTM! 💪