Update telemetry to conform with OTel semantic conventions

[MrAlias]

Ensure all telemetry produced conforms with the latest version of semantic conventions.

[mariomac]

Aggreed in SIG meeting:

As network metrics common spec creation might take long, for milestone 0.1.0, only application-level metrics will conform it.

Network metrics will be either hidden/undocummented or marked as unstable.

[MrAlias]

Closing as it was confirmed above we comply with existing OTel semantic convention. We are working with the semconv group to develop network conventions and will comply when they are created.