docs(apm): add python configuration for trace sampling rules

[majorgreys]

What does this PR do?

Add documentation for DD_TRACE_SAMPLING_RULES for Python tracing configuration in all languages

Motivation

Additional Notes

For translations, in addition to adding DD_TRACE_SAMPLING_RULES above for the Python configs, these DD_TRACE_SAMPLE_RATE and DD_TRACE_RATE_LIMIT are missing from the French and Japanese translations.

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• [ ] Review the URLs listed in the Preview section.
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Preview links (active after the build_preview check completes)

Modified Files

• https://docs-staging.datadoghq.com/majorgreys/AIT-3943/tracing/trace_collection/library_config/python