[Feature] Support environment variables for KubeRay operator chart

[kevin85421]

Why are these changes needed?

I realized that KubeRay operator chart does not support environment variables until #951 (comment).

Related issue number

Checks

• I've made sure the tests are passing.
• Testing Strategy
  • Unit tests
  • Manual tests
  • This PR is not tested :(

# Update values.yaml
env:
- name: EXAMPLE_ENV
  value: "1"

# Install KubeRay operator
helm install kuberay-operator .

# Check Pod 
kubectl get pods kuberay-operator-ffd776d86-xt248 -o jsonpath='{range .spec.containers[*].env[*]}{@.name}{"="}{@.value}{"\n"}{end}'
# EXAMPLE_ENV=1

# Check Deployment
kubectl get deployments.apps kuberay-operator -o jsonpath='{range .spec.template.spec.containers[*].env[*]}{@.name}{"="}{@.value}{"\n"}{end}'
# EXAMPLE_ENV=1

[kevin85421]

cc @Yicheng-Lu-llll @jasoonn

[Yicheng-Lu-llll]

LGTM!

I've also tested the changes as follows(to see if the env var can be truly accessed):

Step 1:
Update the kuberay/helm-chart/kuberay-operator/values.yaml file by adding the following lines:

env:
- name: test
  value: 'test-if-works'

Step 2:
log the environment variable when Reconciling

// in kuberay/ray-operator/controllers/ray/raycluster_controller.go
func (r *RayClusterReconciler) Reconcile(ctx context.Context, request ctrl.Request) (ctrl.Result, error) {
	var err error
	r.Log.Info("get env var", "test:", os.Getenv("test"))

Step 3:
Build a new kuberay image.

Step 4:
Install kuberay using the newly built image by running the following command:
helm install kuberay-operator --set image.repository=kuberay/operator --set image.tag=nightly .

Step 5:
Check the logs of the kuberay operator to confirm the environment variable can be accessed:
kubectl logs $(kubectl get pods -o=name | grep operator)

should see the following output:

root@ip-172-31-14-57:/home/ubuntu/tmp/kuberay# kubectl logs $(kubectl get pods -o=name | grep operator) | grep "get env var"
2023-03-23T04:00:29.487Z        INFO    controllers.RayCluster  get env var     {"test:": "test-if-works"}

[gvspraveen]

LGTM.

Can you update PR description with testing instructions like Yicheng comment?

[kevin85421]

LGTM.

Can you update PR description with testing instructions like Yicheng comment?

Done