HDDS-15903. Fix imagePullSecrets support

[dnskr]

What changes were proposed in this pull request?

The PR fixes imagePullSecrets support to all Ozone pod templates, enabling deployments to clusters that require private registry authentication.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-15903

How was this patch tested?

Render changed templates (excluding om decommission jobs) with provided imagePullSecrets value:

helm template ozone charts/ozone --set "imagePullSecrets[0].name=regcred" --set recon.enabled=true \
  -s templates/datanode/datanode-statefulset.yaml \
  -s templates/om/om-statefulset.yaml \
  -s templates/recon/recon-deployment.yaml \
  -s templates/s3g/s3g-statefulset.yaml \
  -s templates/scm/scm-statefulset.yaml

Output (reduced):

---
# Source: ozone/templates/datanode/datanode-statefulset.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: ozone-datanode
spec:
  replicas: 3
  serviceName: ozone-datanode-headless
  template:
    spec:
      imagePullSecrets:
        - name: regcred
      containers:
        - name: datanode
          image: "apache/ozone:2.1.1"
          ...
---
# Source: ozone/templates/om/om-statefulset.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: ozone-om
spec:
  replicas: 3
  serviceName: ozone-om-headless
  template:
    spec:
      imagePullSecrets:
        - name: regcred
      containers:
        - name: om
          image: "apache/ozone:2.1.1"
          ...
---
# Source: ozone/templates/recon/recon-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: ozone-recon
spec:
  replicas: 1
  template:
    spec:
      imagePullSecrets:
        - name: regcred
      containers:
        - name: recon
          image: "apache/ozone:2.1.1"
          ...
---
# Source: ozone/templates/s3g/s3g-statefulset.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: ozone-s3g
spec:
  replicas: 1
  serviceName: ozone-s3g-headless
  template:
    spec:
      imagePullSecrets:
        - name: regcred
      containers:
        - name: s3g
          image: "apache/ozone:2.1.1"
          ...
---
# Source: ozone/templates/scm/scm-statefulset.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: ozone-scm
spec:
  replicas: 1
  podManagementPolicy: Parallel
  serviceName: ozone-scm-headless
  template:
    spec:
      imagePullSecrets:
        - name: regcred
      initContainers:
        - name: init
          image: "apache/ozone:2.1.1"
          ...

[adoroszlai]

@shuan1026 please review if you have time

[shuan1026]

@adoroszlai Thanks for the ping.

I re-checked the helm template for main workloads with imagePullSecrets[0].name=regcred. And validated on kind cluster that image pull with private Docker Hub repo.

LGTM.

[adoroszlai]

Thanks @dnskr for the patch, @shuan1026 for the review.