Add submodule to set up ACM

[morgante]

We should add a new submodule which can be used to install ACM on a cluster.

This would involve:

1. Deploying the ACM operator
2. Automatically creating an SSH keypair for the operator, uploading it to the cluster (as a secret)
3. Configuring the operator by creating a ConfigManagement resource in the cluster with these required values filled in:

• spec.clusterName
• spec.git.syncRepo
• spec.git.secrectType (hardcode to ssh to start)
• spec.git.policyDir

The module inputs should include:

• cluster ID/self-link
• sync repo
• policy directory
• sync branch (default master)

Outputs should include:

• SSH public key (to give the cluster access to git)

[kopachevsky]

Biggest obstacle implementing this feature is lack of CRD support in terraform provider hashicorp/terraform-provider-kubernetes#215
workaround would be to do stuff with local-exec to run
kubectl apply -f config-management-operator.yaml

[morgante]

Yes, we can use local-exec + kubectl, following the existing pattern.