Zapr log levels don't align with glog/klog recommendations

The named `debug` log level of zap corresponds to the numeric value `-1`, which then gets inverted by zapr and thus corresponds to`V(1)`. At the same time, the Kubernetes logging guidelines assume `V(4)` to be debug level and `V(1)` `A reasonable default log level if you don't want verbosity`: https://github.com/kubernetes/community/blob/905825353d20c57817806dd5aab242ea6c703024/contributors/devel/sig-instrumentation/logging.md#what-method-to-use

So the mapping between the two seems off, furthermore most users of zap are likely to not be aware that the log level is an int8 under the hood and can have values outside of the defined named set. We should find a way so that the named `debug` in zap corresponds to something resembling a debug log level in the glog/klog/logr universe.

Start by reviewing zapr's conversion between zap levels and V-levels, then compare it with the linked Kubernetes logging guidance. Define the desired relationship for named debug and the other levels, and validate that the resulting mapping aligns with glog/klog expectations without relying on undocumented numeric values.

Written by the indexing model from the issue text.