RFC: Add API Objects to define Darkroom instances in Kubernetes

[ajatprabha]

What would you like to be added

Define API objects[CRDs - Custom Resource Definitions] to persist information in Kubernetes' etcd store and use them in the operator to reconcile Darkroom as defined in the CRD.

apiVersion: deployments.gojek.io/v1alpha1
kind: Darkroom
metadata:
  name: darkroom-web
spec:
  source:
    type: WebFolder
    baseUrl: https://example.com/assets
  domains:
    - darkroom-web.named-example.com
  version: 0.1.0

---

apiVersion: deployments.gojek.io/v1alpha1
kind: Darkroom
metadata:
  name: darkroom-aws
spec:
  source:
    type: S3
  bucket:
    name: "myAwesomeBucket"
    region: "region"
    accessKey: "randomAccessKey"
    secretKey: "superSecret"
  pathPrefix: "/prefixPath/to/folder"
  domains:
    - darkroom-aws.named-example.com
  version: latest

Why is this needed

This change will be the first step towards creating an operator that manages a cluster of Darkroom instances and its configuration.

Comments

This is an initial implementation where almost everything is inside Darkroom CRD. In next iteration/improvement we can have separate CRDs to manage Source/Hystrix configs in their own CRD and reference those in Darkroom.