OZG-3328 refactor imagePullSecret

src/main/helm/templates/_helpers.tpl

src/main/helm/templates/deployment.yaml

src/test/helm-linter-values.yaml

src/test/helm/deployment_database_test.yaml

src/test/helm/deployment_defaults_labels_test.yaml

src/test/helm/deployment_defaults_sso_test.yaml

src/test/helm/deployment_image_pull_secret_test.yaml

src/test/helm/deployment_resources_test.yaml

src/test/helm/deployment_spring_profile_test.yaml

src/test/helm/deployment_test.yaml

src/test/helm/deployment_volume_test.yaml