Generate otel metrics from slog event

[mhofman]

What is the Problem Being Solved?

• Replace current metrics generation with a slogSender based reporter
  • removing the current explicit metric generation, to keep a single port (slog sender can run in a sub process)
• Replaces Metrics Parity with Trace attributes #7092
• Relies on Slog ability to record timings #5724 to enable generation of metrics with no or limited state
• Ultimately will integrate with tracing (Rework tracing slog sender #10799)

Description of the Design

Security Considerations

Scaling Considerations

Test Plan

Upgrade Considerations