Add envs in cluster service api

[MissiontoMars]

Why are these changes needed?

Add environment variables in ClusterService create cluster api. The json format looks like:

{
  "name": "test-cluster",
  "namespace": "ray-system",
  "user": "missiontomars",
  "version": "1.13",
  "environment": "DEV",
  "envs": {                            // Add envs here.
        "TEST_ENV2": "10000",
        "TEST_ENV3": "20000"
   },
  "clusterSpec": {
    "headGroupSpec": {
      "computeTemplate": "compute-templates-test1",
      "image": "kuberay/ray_test:91af42534b05995b818f9b4baa3acb57",
      "serviceType": "NodePort",
      "rayStartParams": {
        "node-ip-address": "$MY_POD_IP",
        "port": "6379",
        "dashboard-host": "0.0.0.0"
      },
      "volumes": []
    },
    "workerGroupSpec": [
      {
        "groupName": "workergroup1",
        "computeTemplate": "compute-templates-test1",
        "image": "hub.byted.org/kuberay/ray_test_hdfs:91af42534b05995b818f9b4baa3acb57",
        "replicas": 2,
        "minReplicas": 2,
        "maxReplicas": 2,
        "rayStartParams": {
        "node-ip-address": "$MY_POD_IP"
      },
        "volumes": []
      }
    ]
  }
}

The ray operator set the environment variables in envs fields to all containers in the ray cluster.

Related issue number

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• Testing Strategy
  • Unit tests
  • Manual tests
  • This PR is not tested :(

[MissiontoMars]

@Jeffwan This PR is ready to review. :)

[Jeffwan]

If we already set envs in the podTemplate, this would be unnecessary. this method set additional environments.

[MissiontoMars]

fixed

[MissiontoMars]

@Jeffwan Maybe we can merge this PR now.