FE executive dashboard PoC

What does this MR do and why?

Adds the PoC comparative table for DORA metrics

• Adds the app skeleton
• Adds an API request to fetch both summary and time summary data (DORA metrics are spread across multiple endpoints)
• Adds the basic comparison table
• Adds tests for basic utils

Screenshots or screen recordings

Loading	Loaded with data	Loaded - no previous data	Loaded - no data	Request errors

How to set up and validate locally

Enable dashboard

1. Enable the dashboards page

   Feature.enable(:group_analytics_dashboards_page)

2. Ensure you're on the ultimate plan
3. Visit any Group > Analytics > Dashboards

Seed data

1. Create an environment from the UI named production
2. Open the rails console

   rails c

3. Find the environment id

   // Within the rails console
   $ e = Environment.order(:id)[-1]

4. Seed DORA daily metrics in the environment using the environment

   // Within the rails console
   $ 100.times { |i| Dora::DailyMetrics.create(environment_id: e.id, date: (i + 1).days.ago, deployment_frequency: rand(50), incidents_count: rand(5), lead_time_for_changes_in_seconds: rand(50000), time_to_restore_service_in_seconds: rand(100000)) }

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #373006 (closed)