Migrating from OpenTelemetry Jaeger exporter to OTLP exporter

[ppatierno]

Referring to #7570, the current Jaeger Exporter, used by default when OpenTelemetry is enabled, doesn't have support for TLS via SDK environment variables.
At same time, the Jaeger Exporter is going to be deprecated (details here) and the OpenTelemetry community is pushing for using the OTLP exporter which has TLS support and it's anyway usable with a Jaeger backend which has support for OTLP protocol since 1.35 version.
We should migrate to OTLP Exporter as soon as possible, which means:

• removing the Jaeger Exporter dependency opentelemetry-exporter-jaeger and replacing it with the opentelemetry-exporter-otlp
• making the new OTLP Exporter the default one by setting the OTEL_TRACES_EXPORTER=otlp in our images script or just leaving that env var empty because it will be the default behavior for OpenTelemetry

The migration should be done before the next release, so it also means that the #7588 can be closed and documentation doesn't need any statement around TLS.