Clarify how otel data is processed internally

[StackScribe]

Summary

https://cloud-native.slack.com/archives/C017GAX90GM/p1714418606691249 points out some apparent inconsistencies between "Getting started with Keptn Metrics" and the main documentation about how the otel collector is used by Jaeger. @agardnerIT explains it in his response. We need to improve the documentation to reflect this information.

Technical description

• Add a very brief and high-level explanation to the "Getting started" guide, something like "The following example uses the Jaeger allInOne image, which uses its own collector. The Jaeger installation process bundles the configured OpenTelemetry collector. Other tools, including jaeger-ui without the allInOne image, use the OpenTelemetry collector directly. See for more information
• Add more detailed information in the Otel guide page.

DoD

• Brief explanatory note about how Jaeger allInOne already has the OpenTelemetry collector in the "Getting Started" guide with a link to a more detailed description
• Detailed explanation in the Otel guide page about how the otel collector wrks in case you do not want to use Jaeger allInOne.
• Ensure that all these docs are linked appropriately