feat: Add concurrent result set materialization for driver.Query().Query(...)

[kprokopenko]

What to add
Add a single new option for db.Query(ctx, sql, query.WithConcurrentResultSets(true)) that enables option https://github.com/ydb-platform/ydb-go-sdk/blob/c56ab1faed16406fe3fa874aee6f33cd26eb0ce1/internal/query/execute_query.go#L95

When queries return multiple result sets, some may be computed concurrently. If enabled, parts of different result sets may be interleaved in the response stream.

Out of scope

• All other methods (Session.Query, table.Client, streaming, etc.).
• If the option is omitted, behavior is unchanged.

Benchmark test
Execute 50 independent SELECT statements within a single query and measure wall time:

1. Without the new option.
2. With the new option enabled.

Refactor
Refactor the current implementation to ensure it does not depend on the ConcurrentResultSet option.

[Flak34]

Hello @kprokopenko ! I’d like to take this issue as my coursework project. I’ll implement the ConcurrentResultSets option and perform the required benchmarks.