Add support for open telemetry

[PW999]

We've been using the collector for a while now on a self-hosted prometheus instance and it's been working great for us.
We're now moving to an AWS managed prometheus instance and since it doesn't support pull configs, we're using opentelemetry to pull the metrics and remote write them to the managed prometheus.

However, renaming metrics is disallowed in otel due to open-telemetry/opentelemetry-collector#3410. I've tried different ways to rename the metrics using processors, but to no avail. I've also created a ticket in otel-contib to allow renaming metrics using a processor open-telemetry/opentelemetry-collector-contrib#22735 .

It would be great if the metrics could be exported directly in the correct format without the need for all the metric_relabel_configs to make the dashboards work.