Describe configtelemetry levels

[atoulme]

          Prior to this package's stabilization, I would love it if there were more guidance on what each of the levels are for. Right now the documentation is very vague and I think the differences between normal & detailed are not specific enough. This is almost a flavor of #7543 where that metric could have been enabled only in the "detailed" configuration, however, reserving "detailed" that way wasn't an option because we put many metrics behind "detailed" that I would argue belong more in the "normal" or "basic" levels ([ex](https://github.com/open-telemetry/opentelemetry-collector/blob/main/processor/batchprocessor/metrics.go#L65-L67) of a detailed metric that IMO should be a "normal" metric).

Originally posted by @jaronoff97 in #10277 (comment)

[atoulme]

@jaronoff97 I'm trying to understand if this should block the package stability. Are you looking for better documentation and guidelines or changes to the behavior of the package content? If it's the former, I'd vouch for removing this from the 1.0 milestone.