Add camera optical_frame_id element

[MarqRazz]

🎉 New feature

This adds the ability to specify the optical frame_id that will be used when publishing the camera_info topic from a simulated sensor. This feature request was noted in CameraSensors.cc and will help close https://github.com/ignitionrobotics/ign-sensors/issues/175 in ign-sensors.

Summary

Adds optional sdf element optical_frame_id that the simulated camera can utilize. I will make a PR in ign-sensors to utilize the new element after this PR is merged.

Checklist

• [x] Signed all commits for DCO
• [x] Added tests
• [ ] Added example and/or tutorial
• [ ] Updated documentation (as needed)
• [ ] Updated migration guide (as needed)
• [ ] Consider updating Python bindings (if the library has them)
• [ ] codecheck passed (See contributing)
• [ ] All tests passed (See test coverage)
• [ ] While waiting for a review on your PR, please help review another open pull request to support the maintainers

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