Support MultiQueryTracer

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By using the `MultiQueryTracer` proposed in the following PR, I was able to set tracer and logger respectively.
I thought this is a case that other people might need.

- https://github.com/jackc/pgx/issues/1061

Do you plan to incorporate this into the pgx itself?

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I'd be happy to see it implemented in the pgx itself.

**Appendix**
- https://github.com/jackc/pgx/discussions/1677

Start by reading the proposed MultiQueryTracer PR in issue #1061 and the related discussion in #1677, then examine how pgx currently handles tracers and loggers. Done means agreeing on and implementing native support for separately configured tracing and logging in pgx.

Written by the indexing model from the issue text.