Jenkins module created out of contint manifests

misc::contint contained a Jenkins class for the continuous integration.
I have extracted out the part which are only related to Jenkins in a new
Jenkins module.  Simply 'include jenkins' and you get an installation.

Moved the jenkins group definition to the module, dropping GID 561 in
the process and letting puppet manage it for us.

The Jenkins instance might need to be proxying via Apache, that
configuration is not part of the jenkins module.

Change-Id: I33bce60e08fd4c1e8184d6fac5ba0d3f9798fe35
Merge "Jenkins module created out of contint manifests" into production