[Development][Add] Added imagePullSecrets support (#128)

api/v1beta1/common_types.go

api/v1beta1/zz_generated.deepcopy.go

config/crd/bases/redis.redis.opstreelabs.in_redis.yaml

...g/crd/bases/redis.redis.opstreelabs.in_redisclusters.yaml

example/redis-cluster.yaml

example/redis-standalone.yaml

k8sutils/redis-cluster.go

k8sutils/redis-standalone.go

k8sutils/statefulset.go