Allow Resource Creation with conditions

[mnkg561]

Is this a BUG REPORT or FEATURE REQUEST?: FEATURE REQUEST

What happened: By default, all the resources will be created in asynchronous calls. There might be a chance where one of the k8s resource is dependent on other resource. For example: To create RoleBinding you must have Role and Service Account already exists. We should allow option to provide the dependency structure if one needed.

This should be part of Namespace Template as well as ManagedNamespace (well, behind the scenes its using same struct)

What you expected to happen: For ex: In following template, controller should create service account only after Role is created successfully.

    resource:
      - name: local_service_account2
        type: ServiceAccount
        dependsOn: local_role
        serviceAccount:
          apiVersion: v1
          kind: ServiceAccount
          metadata:
            name: ${env}-sa2
            namespace: ${name}
      - name: local_role
        type: Role
        role:
          apiVersion: rbac.authorization.k8s.io/v1
          kind: Role
          metadata:
            name: ${env}-role
          rules:
            - apiGroups:
                - ""
              resources:
                - pods/attach
                - pods/exec
              verbs:
                - get
                - list
                - watch
                - create

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:

Environment:

• manager version
• Kubernetes version :

  $ kubectl version -o yaml

Other debugging information (if applicable):

- controller logs:

$ kubectl logs

[mnkg561]

We have to be careful with circular dependency and all resources with "dependsOn" variable.

[mnkg561]

This should also provide the condition if resource have to be created only once and should not be overwritten after that. This might be useful in a case where administrator can provide default value but namespace owners can always update based on their requirements directly on the managed cluster itself using any CICD tool.