LogConfigurator resolveConfig  also reads .rpmnew or .bak files

Currently the LogConfigurator will attempt to read any file that starts with "logging." in the env.configFile() path.

A common practise is to suffix files with .bak or in case of package managers they often add a suffix if the file has been modified upstream.

Elasticsearch will read those values anyway and that might lead to very confusing logging behaviour.

I am not sure how to best approach this, either have a whitelist or a backlist of suffixes that are allowed/disallowed ?
I see what you mean, that we somehow break bw comp but I would leave only the lowercase variants to make this consistent with other places where we load files e.g. we would never load `elasticsearch.YML` . I think this change is acceptable and in the scope of the PR since we are in fact limiting the files that are getting loaded as logging configuration.