feat: Add HTTP OTLP trace exporter support for auto instrumentation

[hoperawr]

Description

This PR introduces support for selecting the OTLP exporter protocol based on the OTEL_EXPORTER_OTLP_PROTOCOL environment variable, enabling users to choose between gRPC and HTTP/protobuf transports for telemetry data export. The default will be gRPC if the variable is not set, ensuring backward compatibility.

Related Issue

Closes #17

Type of Change

Please check the relevant option:

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Code refactoring
• Dependency update

How to Test

Describe how reviewers can test your changes:

1. Add environment variable OTEL_EXPORTER_OTLP_PROTOCOL="http/protobuf"
2. Use auto_instrument function
3. Traces will be exported using HTTP protocol

Checklist

Before submitting your PR, please review and check the following:

• I have read the Contributing Guidelines
• I have verified that my changes solve the issue
• I have added/updated automated tests to cover my changes
• All tests pass locally
• I have verified that my code follows the Code Guidelines
• My code does not contain sensitive information (credentials, tokens, etc.)
• I have followed Conventional Commits for commit messages

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[LucasAlvesSoares]

The lazy import approach works, but I'd suggest moving the imports to the top level instead.

Top-level imports are the standard Python convention (PEP 8) and make the dependencies of the module immediately visible to readers.

Since both opentelemetry-exporter-otlp-proto-grpc and opentelemetry-exporter-otlp-proto-http are declared as required dependencies in pyproject.toml, they will always be present, so we don't need to defer the import. Lazy imports are a useful pattern when a dependency is optional or heavy to load, but neither applies here.

[LucasAlvesSoares]

By the way I like the idea of raising a ValueError.