feat: Add mTLS support for TracePipeline OTLP output

[dennis-ge]

Description

Changes proposed in this pull request:

• add support for TLS certificates for the TracePipeline and MetricPipeline OTLP Output
• The E2E test is included in a separate PR.

Related Issues and Documents

Closes:

Related issues: kyma-project/kyma#17995

Traceability

• The PR is linked to a GitHub Issue.
• New features have a milestone label set.
• New features have defined acceptance criteria in a corresponding GitHub Issue, and all criteria are satisfied with this PR.
• The corresponding GitHub Issue has a respective area label.
• The follow-up issues (if any) are linked in the Related Issues section.

Testability

The feature is unit-tested:

• Yes.
• No, because unit tests are not needed.
• No, because of ...

The feature is e2e-tested:

• Yes.
• No, because e2e-tests are not needed.
• No, because the e2e-test will be introduced in a later PR

Tests conducted for the PR:

• Created multiple TracePipelines with different tls configurations to see how the otel collector reacts

Codebase

• My code follows the Effective Go style guidelines.
• The code was planned and designed following the defined architecture and the separation of concerns.
• The code has sufficient comments, particularly for all hard-to-understand areas.
• This PR adds value and shows no feature creep.
• I have augmented the test suite that proves my fix is effective or that my feature works. (unit tests only)
• Adjusted the documentation if the change is user-facing.

[kyma-bot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[dennis-ge]

/test all

[dennis-ge]

/test all

[dennis-ge]

I restored the isInsecureOutput function that checks if the endpoint scheme is http. It is necessary that this is set before line 82 (output.TLS == nil) to have the same functionality as before.

This line checks if the output is not insecure, i.e., line 80 (cfg.Insecure = isInsecureOutput(otlpEndpointValue)) returned false. If this is the case, we allow to overwrite the TLS setting.

It is not a nice solution but it should be the same as the behavior before

[chrkl]

This function is more generic than it's name. Let's either make 3 specific function for each purpose or use a more generic name.

[dennis-ge]

/retest-required

[chrkl]

/retest

[kyma-bot]

@dennis-ge: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-telemetry-manager-governance	98a75d2	link	false	/test pull-telemetry-manager-governance

Full PR test history. Your PR dashboard.

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