python: Use private logger instead of root logger

[vrslev]

The library currently uses the root logger, which can be problematic when you want to suppress these logs. This is particularly relevant for pyroscope.shutdown(). To address this, I have introduced the use of a private logger in pyroscope.shutdown(), and also in pyroscope.configure() for consistency.

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[vrslev]

@grafana/pyroscope-rs

[korniltsev]

Thanks!