[APM] Updated header icons

[smith]

(Part of the new APM service overview. See #81135 for more.)

The main header will be updated to make it consistent with the other Observability apps.

Apart from the re-arrangements, we'll be adding new icons at the top to indicate the service agent, container, and cloud metadata.

🖼 View screens

Service

• Service version
• Runtime name & version
• Framework name
• Agent name & version

Container

• OS
• Containerized
• Average number of instances
• Orchestration

Cloud

• Cloud provider
• Availability zone(s)
• Machine type(s)
• Project ID

Handling unknown entities

In the case where either the agent name, container orchestration or cloud provider isn't on our "most common" list, we will show a fallback monotone icon instead so the information is still available.

• Agent: node (same fallback as in Service Maps)
• Container orchestration: storage
• Cloud provider: cloudSunny

[elasticmachine]

Pinging @elastic/apm-ui (Team:apm)

[formgeist]

Added an example of fallbacks in the issue description for either entity in the header icons

[formgeist]

Opened an issue to track the definitions for the container orchestration and cloud provider icons #84738

[formgeist]

@cauemarcondes We arrived at a shortlist of container orchestration platforms and cloud providers, all of which we have logo SVGs for in our EUI icon set as per #84738 (comment)