Log a warning when instrumenting a cache that is not recording stats

[keith-turner]

Please describe the feature request.
It would be nice if a warning were logged (or the user was informed in some way) when a cache is instrumented that is not recording stats.

Rationale
For some Cache implementations like Caffeine recording stats is optional. When instrumenting a cache that is not recording stats the meters will constantly report 0 which could be misleading. This is probably not what the user desires.

Additional context

apache/accumulo#4552