docs: Add OTLP Logs PoC documentation

[chrkl]

Description

Changes proposed in this pull request (what was done and why):

• Add documentation about OpenTelemetry logging PoC

Changes refer to particular issues, PRs or documents:

• PoC for Log parsing with Otel Collector #720

Traceability

• The PR is linked to a GitHub issue.
• New features have a milestone 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 and kind label.
• The follow-up issues (if any) are linked in the Related Issues section.
• Adjusted the documentation if the change is user-facing.
• The feature is unit-tested
• The feature is e2e-tested

[chrkl]

/hold

[chrkl]

/unhold