[Logs UI] Refactor log stream page state

[weltenwort]

📓 Summary

In order to support upcoming features like the unified search bar's filter support and to improve the robustness of the page, we want to clean up the way the page manages and renders its state.

✔️ Acceptance criteria

• xstate and xstate-react are Kibana dependencies and managed by renovate
• Implement a state machine to model the initialization of the page:
  • uninitialized ➡️ loading log view ➡️ has log view
• The "loading log view" state communicates with the separate log view resolution actor.
• The short-circuiting logic in the LogsPageProviders component is made unnecessary.

Bonus achievements

• The state machine is implemented in a package (such as packages/observability-logs/log-stream-page/state.
• The state machine provides strict types, that are derived via typegen as part of the bazel build process.

💡 Implementation hints

Page state machine draft

Potential package structure

• log-stream-page/state
• log-stream-page/query-state
• log-stream-page/datepicker-state
• log-stream-page/filter-state
• log-stream/log-entries-state
• log-stream/log-histogram-state
• log-view-state

[elasticmachine]

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