fix: Remove trace code sample that use OpenCensus

[minherz]

Description

Remove trace code sample that use OpenCensus. The whole folder is removed to reflect the migration of the public documentation to use OpenTelemetry in its samples.

Fixes #8423

[snippet-bot[bot]]

Here is the summary of changes.

You are about to delete 2 region tags.

• trace/trace-python-sample/main.py:22, tag trace_setup_python_configure
• trace/trace-python-sample/main.py:48, tag trace_setup_python_quickstart

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[minherz]

It is save to merge the changes (see cl #481664523 for documentation changes)

[minherz]

@dandhlee / @parthea can you approve this PR please?

[minherz]

If there is a replacement for this sample available elsewhere, can you update to something like this: https://github.com/GoogleCloudPlatform/python-docs-samples/tree/main/document

@dandhlee thank you for taking the look. This example was solely used by the documentation page that was taken down. See my comment for change list id. The OpenTelemetry example is used by the designated OT documentation. Please, have a look at #8424 for more details.

[dandhlee]

I took the [tracing sample](https://github.com/GoogleCloudPlatform/python-docs-samples/tree/2f10c77e5247eaf6237915311e1d98cb3dae1701/trace/trace-python-sample) should be taken down and replace with the [code sample](https://github.com/GoogleCloudPlatform/opentelemetry-operations-python/blob/HEAD/docs/examples/cloud_trace_exporter/advanced_trace.py) that uses OpenTelemetry. as that the sample being removed, is equivalent and/or favored by the sample mentioned in the opentelemetry-operations-python sample. If that's the case, other folks might have bookmarked / mentioned the link to the sample being deleted here. We should kindly direct them to take a look at the new sample, rather than just removing it altogether and leading them to 404s.

Let me know if I misunderstood that.

[minherz]

I got your point. Makes sense. I will update the README.rst to instruct looking into another folder.