feat(*) add key helm.sh/hook-delete-policy to hook annotation

When "helm.sh/hook-delete-policy: hook-succeeded" is provided in a hook's annotation, Tiller will automatically delete the hook after the hook is succeeded. When "helm.sh/hook-delete-policy: hook-failed" is provided in a hook's annotation, Tiller will automatically delete the hook after the hook is failed.

Closes #1769