feat(tracing): use OTEL_PROPAGATORS as per OTel spec

[hacdias]

• Superseds feat: set default OTel propagator #9169 and feat: support OTel tracing in gateway with correct propagators #9798
• Adds support for OTEL_PROPAGATORS environment variable as defined in the specs, using the autoprop package:
  • https://pkg.go.dev/go.opentelemetry.io/contrib/propagators/autoprop#NewTextMapPropagator
  • https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/sdk-environment-variables.md#general-sdk-configuration
  • Default is still TraceContext and Baggage

[hacdias]

The proof via cat'ing as requested by @Jorropo

make build
OTEL_TRACES_EXPORTER=jaeger ./cmd/ipfs/ipfs daemon
OTEL_TRACES_EXPORTER=jaeger ./cmd/ipfs/ipfs cat bafkreifjjcie6lypi6ny7amxnfftagclbuxndqonfipmb64f2km2devei4

[Jorropo]

We should reconsider screenshot based test suite but testing tracing sounds painfull.

[hacdias]

@Jorropo yeah, we have a small test for the Boxo example because we can. In Kubo seems much harder to do.