jdbc: integrate log4jdbc-log4j2

Update to the latest platform code to get log4jdbc-log4j2 support.
The default logback.xml configuration will print out only sqltiming logs,
grouped by thread name.

Grouping by thread name may not be what we want ultimately: although it
helps having bus and notification queues stats in their own files, since we have
several plugin threads and thread pool executors, the other queries
end up spread across several files.

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>
Merge branch 'master' of github.com:killbill/killbill
Merge branch 'master' of github.com:killbill/killbill
log: updates to ThreadNameBasedDiscriminator

Make it smarter and group log events by killbill or commons submodule.

This adds some overhead to the calls, between 1ms and 9ms in my testing.

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>
log: tweaks to the default logback

* Fix the default path for rotated files
* Enable gzip compression

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>