[Metrics UI] Remove saved object concept from browser and HTTP APIs

[weltenwort]

📓 Summary

In order to allow the browser-side code to work seamlessly across Kibana server upgrade without a page reload, we want to have fully versioned HTTP APIs that are not tied to any the internal saved object schema. To that end, we must neither access the saved object client from public code nor leak the saved object schema in HTTP requests and responses.

🔗 part of #149098

🔢 Tasks

• [Metrics UI] Created new HTTP endpoints for Saved Views functionality #152617
• [Metrics UI] Decouple source config HTTP API schema from saved object schema #152279

[elasticmachine]

Pinging @elastic/infra-monitoring-ui (Team:Infra Monitoring UI)

[roshan-elastic]

Hey @weltenwort, trying to understand the user impact of this.

It sounds like this would mean that when a Kibana server is upgraded, the user wouldn't experience any issues when it upgrades?

Do you have any details on when a Kibana server is upgraded and the current experience for the user?

[neptunian]

@roshan-elastic These were both completed, just forgot to close this parent issue. Ping me if you'd like more info.