feat(tracer): add OpenTelemetryProvider implementation (#7003)

[Alwaysgaurav1]

Issue number: closes #7003

Summary

Changes

• Implemented OpenTelemetrySegment and OpenTelemetryProvider in aws_lambda_powertools.tracing.opentelemetry.
• Exported OpenTelemetryProvider and OpenTelemetrySegment from aws_lambda_powertools.tracing.
• Added unit tests covering segment attribute set, exception recording, subsegment context managers, and Tracer decorator integration in tests/unit/test_opentelemetry.py.

User experience

Users can now pass an OpenTelemetryProvider to Tracer to send trace data to OpenTelemetry backends:

from aws_lambda_powertools import Tracer
from aws_lambda_powertools.tracing import OpenTelemetryProvider

provider = OpenTelemetryProvider()
tracer = Tracer(service="my-service", provider=provider)

@tracer.capture_method
def handler(event, context):
    return "ok"

[boring-cyborg]

Thanks a lot for your first contribution! Please check out our contributing guidelines and don't hesitate to ask whatever you need.
In the meantime, check out the #python channel on our Powertools for AWS Lambda Discord: Invite link

[sonarqubecloud]

Quality Gate passed

Issues
5 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[powertools-for-aws-oss-automation]

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