Change LoggerAdapter extra field to accomodate to OpenTelemetry

[RoggeOhta]

What was changed

Logger adapter's extra field format; flatten the "temporal_activity/activity_info/temporal_workflow/workflow_info" in extra fields.

Why?

To accomodate to opentelemetry format, because opentelemetry's attributes only takes (bool, str, bytes, int, float)

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[cretz]

Commented on #837 issue.