contint: logs directory to hold Jenkins console logs

The console logs are going to be extracted out of Jenkins and published
as flat files.  That would let us publish artifacts such as MediaWiki
debugging log as well as the console output and offload Jenkins a bit.

The /logs/ directories hierarchy should be browseable.

Change-Id: Ia1cd28e43d296da1a22155a01b98b2f05c37732d