config and apply subcommands

[arapulido]

As discussed int the UX document for the CLI, we want the install command to be a composed command that can be split into config and apply

Right now only the install command exists. We should create the subcommands config and apply

[falfaro]

It is probably best to just implement a new subcommand named like generate which creates all the relevant objects in the underlying platform (GKE, AKS) and then generates the JSON configuration file and jsonnet root manifests.

From that point, users can customise the root manifest at will and then run kubeprod install to deploy the changes to production. No need for a kubeprod apply subcommand.

[anguslees]

PR #232 probably addresses this issue, but not with the solution(s) described above.

[anguslees]

Fixed in #232