Removed deprecated loglevel in otel-collector config

[madwort]

loglevel is deprecated

https://github.com/open-telemetry/opentelemetry-collector/blob/v0.71.0/exporter/loggingexporter/README.md#note

we use the same var elsewhere tho, so needs a tiny bit of rework

[alarthast]

As of otel/opentelemetry-collector-contrib v0.111.0 the logging exporter has been removed.

We should either suppress dependabot PRs for otel/opentelemetry-collector-contrib, or switch to using the debug exporter with verbosity (see #220; we will also need to check for use cases on dokku4, perhaps?)