Add new workspace:inject --kubeconfig command

[l0rd]

The command syntax:

Inject configurations and tokens in a Che Workspace

USAGE
  $ chectl workspace:inject

OPTIONS
  -k, --kubeconfig                  Inject the local Kubernetes configuration
  -h, --help                        show CLI help
  -w, --workspace=workspaceid       Target workspace
  -c, --container=containerid      [default: dev] Target container
  -n, --chenamespace=chenamespace   [default: kube-che] Kubernetes namespace where the workspace is deployed

When the command is executedchectl should look at local ~/.kube/config and:

• generate a new ~/.kube/config to copy it in the target container
• copy certificates and keys in the target container

More details about the expected behaviour of the command:

• If a ~/.kube/config already exist in the target container the command should fail (we may later add a --force flag but that's not in the scope of this issue)
• The --workspace flag can be omitted only if there is just one running workspace (if will fail otherwise)
• If the --container flag is omitted the default container should be the che-dev (it will fail if che-dev doesn't exist)