SDKLogLevel field

[pinoOgni]

Hi folks!

I noticed that the SDKLogLevel field in MetricsConfig and in TracesConfig have the same env variable name OTEL_EBPF_SDK_LOG_LEVEL () but the supported values are different.

1. SDKLogLevel in MetricsConfig is used as slog.Level which accepts: debug, info, warn and error
2. SDKLogLevel in TracesConfig is used as zapcore.Level which accepts: debug, info, warn/warning, error, dpanic, panic and fatal

I wanted to change the name of the environment variable, something like OTEL_EBPF_METRICS_SDK_LOG_LEVEL and OTEL_EBPF_TRACES_SDK_LOG_LEVEL, but this is a breaking change, so I'd like to hear your opinion first.