Operator should expose metric(s) for ConfigCheck failures and/or `Logging` object problems

[marvin-roesch]

Is your feature request related to a problem? Please describe.
If a config check fails, the triggering Logging resource gets its status updated with a problem, but there is no metric like logging_resource_problems exposed for this.

Describe the solution you'd like
The operator should expose some metric that reflects config check failures. Expanding the logging_resource_problems metric to encompass a Logging object would also be nice.

Describe alternatives you've considered
A custom solution reacting to the Logging status change would work. Checking and alerting on the created pod failing is also viable. That feels a little roundabout and brittle since the way the config check is performed is more of an implementation detail.