Config removing detailed spans

[Artur-Sulej]

This PR adds configuration flag emit_detailed_spans passed to SpandexEcto.EctoLogger.
This flag can be set either in application config:

config :spandex_ecto, SpandexEcto.EctoLogger, tracer: MyApp.Tracer, emit_detailed_spans: false

Or via the config argument in :telemetry.attach/4

:telemetry.attach(
  …
  &SpandexEcto.TelemetryAdapter.handle_event/4,
  emit_detailed_spans: false
)

This config is later passed to SpandexEcto.TelemetryAdapter.handle_event/4 (it happens in execute).

Setting emit_detailed_spans: false will result in removing spans queue, run_query and decode, leaving only query span.
The change backward compatible. The default value (when the flag is not set) is true, meaning that the details spans are emitted like without this change.