[Security Solution][Meta] Detection & Response dashboard implementation

[semd]

Engineering issue from: https://github.com/elastic/security-team/issues/2080

Summary

Implement the first version of the Detection & Response dashboard on a new page within Security Solution.

Design:

Figma link

Discussions document link

Scope

The scope for this first version does NOT include:

• Favourite button
• All percent variation badges
• KPIs section
• "SOC Trends" section
• "Rules by false positive" section

Tasks

Metrics Data hooks

We need to create the data hooks that will serve the data from the aggregation queries, in order to get the counters + table data to show in the dashboard sections. They will be implemented along with the UI components of each section.
The sections are the following:

General

• [Security Solution][Detection & Response] Create new page with main parts #127865
  • Add navigation item under a new feature flag
  • Implement the header time range selector with refresh button
  • Implement "updated at" info
  • Prepare containers to perform the API queries

Sections

• Implement alerts counters charts section with and links to /alerts #128476
• Implement cases counters query by status (depends on [Cases] Provide apis to query cases from the UI #128483)
• [Security Solution][Detection & Response] Open alerts by Rule table #128478
• Implement cases recently opened query #131028
• Implement alert severity by host and user queries #129554

Release

• Removal of experimental flag, unification refactor if needed, and integration tests (cypress).

[elasticmachine]

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