[Tech Debt] Increase folder structure consistency

[CoenWarmer]

Summary

As discussed with the team in AO Team Talk, we would like to make some adjustments to the Observability App so they have better organization and pages are more consistent with each other. In addition it cleans up dead and unused code and moves shared components and utilities into a dedicated plugin.

The decisions made can be found in the presentation here: https://docs.google.com/presentation/d/1N7R37pn_EUyOuHmdTT4qJ6n8M0BFEl4HF0r1G8FhDdg/edit?usp=sharing

This is the epic that contains all the tasks related to that work.

Phase 1: Update page components

• Adjust folder structure in Overview page #152787
• Adjust folder structure in Alerts page #152788
• Adjust folder structure in Alert Detail page #152789
• Adjust folder structure in Rules page #152790
• Adjust folder structure in Rule Detail page #152791
• Adjust folder structure in SLO List page #152793
• Adjust folder structure in SLO Detail page #152794
• Adjust folder structure in SLO Edit page #152795
• Adjust folder structure in Cases page #152985

Phase 2: Exploratory View

• [Observability][Synthetics] Move Exploratory View route into a separate app #153830
• [Exploratory View] Update links to Exploratory View in APM app #153883
• [Observability] Redirect users from app/observability/exploratory-view to app/exploratory-view #153940
• [Observability] Remove Playwright E2E from Observability #153884
• [Exploratory View] Update UX app to use components from Exploratory View app #154053
• [Exploratory View] Update Synthetics app to use components from Exploratory View #154055
• [Tech Debt] Update E2E setup for Exploratory View app #154755
• [Observability] Remove Exploratory View components from Observability app #153933

Phase 3: Observability Shared & Observability Page Template

• [Observability] Add Observability Shared app to house shared components #154735
• Use Observability Page Template from Observability Shared in Ux, Uptime and Synthetics #154773
• Use Observability Page Template from Observability Shared in APM and Profiling #154775
• Use Observability Page Template from Observability Shared in Infra #154777
• Use Observability Page Template from Observability Shared in Observability app #154779

Phase 4: Move shared hooks and components to Observability Shared

• Move useTrackMetric hook to Observability Shared #157274
• Move shared hooks and components to Observability Shared #157848
• [APM] Update imports to Observability Shared #157850
• [Infra] Update imports to Observability Shared #157852
• [Observability Onboarding] Update imports to Observability Shared #157853
• [Synthetics][UX] Update imports to Observability Shared #157857
• [Profiling] Update imports to Observability Shared #157855

Phase 5: Update Observability App folders

• Update Observability folder structure #153308
• Remove duplicate App Services type  #158143
• Consolidate route configuration #158146
• Clean up /config and /components folders #160556

[elasticmachine]

Pinging @elastic/actionable-observability (Team: Actionable Observability)