Provide OpenTelemetry semantics compatibility

[stevapple]

Is your feature request related to a problem? Please describe.
Database spans from Dacalog are not recognized by APM dashboards.

Describe the solution you'd like
We would like to make Decalog OTel-compatible. OpenTelemetry has a set of semantic conventions for tagging a span, which is recognized by some APM dashboards.

Describe alternatives you've considered
We can run a "shim" between Decalog and OpenTelemetry backends, but that’s extra amount of work and may be difficult for most users.

A potential solution is introducing hooks into Decalog, to let users modify tags of all traces.

Additional context
https://opentelemetry.io/docs/reference/specification/trace/semantic_conventions/