[Security Solution][One Discover] Migrate user flyout and related subcomponents

[kelvtanv]

Summary

• factor out the ObservedDataSection to be a shared component
• factor out shared tools between entities (for example see: x-pack/solutions/security/plugins/security_solution/public/flyout_v2/entity/shared/tools/alerts_insights/index.tsx), its a wrapper over the main content located outside of the flyout directories
• add the entities tool for the alert document on preview header click
• column renderers for user.name

Checklist

Check the PR satisfies following conditions.

Reviewers should verify this PR satisfies this list as well.

• 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
• If a plugin configuration key changed, check if it needs to be allowlisted in the cloud and added to the docker list
• This was checked for breaking HTTP API changes, and any breaking changes have been approved by the breaking-change committee. The release_note:breaking label should be applied in these situations.
• Flaky Test Runner was used on any tests changed
• The PR description includes the appropriate Release Notes section, and the correct release_note:* label is applied per the guidelines
• Review the backport guidelines and apply applicable backport:* labels.