Declarative config for logback appender installer

[zeitlinger]

fixes #15812

[trask]

what is the "or legacy" part of this method?

[zeitlinger]

inlined it right into the method for clarity

    String key = property;
    if (EarlyConfig.isDeclarativeConfig(environment)) {
      if (property.startsWith("otel.instrumentation.")) {
        key =
            String.format(
                    "otel.instrumentation/development.java.%s",
                    property.substring("otel.instrumentation.".length()))
                .replace('-', '_');
      } else {
        throw new IllegalStateException(
            "No mapping found for property name: " + property + ". Please report this bug.");
      }
    }

[zeitlinger]

can also do the translation the other way round - but it's still a flat string