Adapt existing Elasticsearch instrumentation to comply with semconv proposal

[AlexanderWert]

There is a proposal on semantic conventions for Elasticsearch spans:
open-telemetry/opentelemetry-specification#3358

To better understand the impact of that proposal on existing Elasticsearch instrumentation in the Java agent, it's worth creating a PR that implements the mentioned proposal.

[AlexanderWert]

Will create a corresponding PR.