switch to structured logging

[hrodmn]

Rather than unstructured logs with dot notation for nested categories we could switch to a structured logging approach.

See https://newrelic.com/blog/how-to-relic/python-structured-logging as suggested by @geospatial-jeff in #1171

[vincentsarago]

@hrodmn I would love to add this before we do a next release 🙏

[hrodmn]

I got started on this a while ago but got stuck getting opentelemetry traces/spans to be automatically injected into the structlog logs. It was easy to do with the standard logging module because of existing fixtures in the opentelemetry libraries, but structlog does not yet have a built-in integration (issue: open-telemetry/opentelemetry-python#2993).

It looks like it is possible to do (e.g. https://github.com/a1403951401/ez_otlp/blob/main/ez_otlp/log/structlog_config.py) but do we want to add this type of complexity in titiler?

[vincentsarago]

thanks @hrodmn I think we can wait for open telemetry to support structlog then 🙏