Add OpenTelemetry support for observability

### Is your feature request related to a problem?

Private Mirrors should have strong observability out of the box, including metrics, tracing, and logs. This will make it easier for those running Private Mirrors to observe the function of the application.

### Describe the solution you'd like

[OpenTelemetry](https://opentelemetry.io/) is a standard open source framework for observability that is widely supported by vendors and cloud or hosting providers. Private Mirrors should add native support for OpenTelemetry.

### Describe alternatives you've considered

Continue with existing observability (primary logging).

### Additional context

#450 is somewhat related