Add Open Telemetry support to the pulp-content app

[decko]

Feature

Adds open telemetry metrics support to the pulp-content app. For example, it should report response codes and latency of all requests the content app handles.

Implementation

Option A: Use the aiohttp-server telemetry support from upstream

This would include use picking up the dependency opentelemetry-instrumentation-aiohttp-server and enabling it in pulpcore like this. Also we would add some tests for it.

To pursue this option the upstream PR needs to be merged and released to PyPI.

Option B: Vendor the upstream not-merged-not-released aiohttp-server telemetry support

This involves us vendoring the unmerged or unreleased upstream code temporarily into Pulp. Since we're bringing the code it doesn't involve us picking up a dependency. It would still need to be enabled in pulpcore like this. We would still need to add tests for it just like Option A.

This option is a temporary option. Option A is really the only long-term option.