Add a cluster_ee.txt docopt file
Add a cluster_ee.txt docopt file

This is a copy of cluster.txt which extends it by adding a link and
unlink command.

The docopt file for the cluster subcommand would then be retrieved
programmatically depending on the availability of the cluster linker API
service.

kensipe/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli,kensipe/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli,dcos/dcos-cli,dcos/dcos-cli