Update log4j `rootLogger`

`stdout` doesn’t really make sense since both stdout and stderr are
redirected to `/dev/null` in the init.d script(s).

Log everything (that isn’t explicitly configured to be logged elsewhere)
to `<log dir>/kafka.log`.
Remove `LogCleaner` logger

The appender doesn’t even exist in the bundle configuration file, and it
is easy enough to just add the configuration if one wants it.
Roll over log files on a daily basis

Rather than an hourly as from what I’ve seen during a quite small
experiment is that Kafka doesn’t generate any significant amount of log
content.
Make it easier to override logging config.

The previous structure did make it a but cumbersome to override for
example the appender type, while this structure (essentially only
hashes) makes it a bit easier.