Allow use of Jenkins from the command line

Extracts the jenkins-cli jar and puts it alongside the war file in /usr/lib/jenkins. The method describes on https://wiki.jenkins-ci.org/display/JENKINS/Jenkins+CLI suggested obtaining the jar file via HTTP while the service is running. My method extracts the jar file manually from the war file as this is more reliable than wget. It also does not have a dependency on Service['jenkins'].

I'd like to include this class by default in jenkins/init.pp, but am unsure where to put it.