Native OpenTelemetry integration

OpenTelemetry is a collection of tools, APIs, and SDKs. You use it to instrument, generate, collect, and export telemetry data (metrics, logs, and traces) for analysis in order to understand your software's performance and behavior.

It's yet to be seen how much traction OpenTelemetry gains, but it seems to be getting embraced by large actors.

OpenTelemetry Python instrumentation actually has a Falcon 2.0 instrumentation plugin!

It would be great to extend this instrumentor for the upcoming Falcon 3.x series. Some things that I expect to break or be missing:

• falcon.API :arrow_right: falcon.App renaming might not get picked by the plugin's monkey patching unless one is using the deprectated API alias
• Falcon ASGI support
• The plugin's error heuristics could probably use our insights (do not rely on exception names etc)
• Anything else?

Related/a subset of: #10