query trace

Expose the execute info of each step to end user.

Still not well defined of those concepts

**execute info**
- execute time
- execute result (row data)

**step**
A query is executed by one or multiple runner plan

**end user**

Trace info can be available in cli and SDK. A system variable can exists to control run query trace on/off (off default).

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*A general feature, open as issue for further tracking.*

The issue mentions exposing execute info (time, result) per step of a query runner plan to end users via CLI and SDK, with a system variable to toggle tracing. Start by examining the query execution engine and runner plan structure in the codebase. Look for existing logging or profiling mechanisms. Determine how to instrument steps to collect trace data and expose it through the CLI interface and SDK APIs. Define what a 'step' entails and how the trace data should be formatted.

Scritto dal modello di indicizzazione a partire dal testo della issue.