quarkus-micrometer-opentelemetry doc improvements

[brunobat]

Add more context to Micrometer metrics output comparison table at quarkus-micrometer-opentelemetry.
Update outdated links to the OTel project.

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Status for workflow Quarkus Documentation CI

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[michalvavrik]

I can confirm that having the links for OpenTelemetry terms helped me to understand what this table means, and to correct my expectations. Also saying as seen in the OTLP output helps to understand what is the "The bridge Opentelemetry output name" as Prometheus transforms it to a different format. Also /q/metrics helped, I checked and I can see that I can compare the metrics.

Thanks for the help @brunobat , the guide is easier for me to understand, I don't have more points to clarify.

[brunobat]

Thanks @michalvavrik for raising this.