Added --controller feature

Previously we used to mention controller type as `--deployment`,
`--replication-controller` or `--daemonset` as argument.
But now,
it will be like,

ex.

```
kompose convert --controller=daemonset
```

pkg/kobject/kobject.go

@@ -51,6 +51,7 @@ type ConvertOptions struct {
 	OutFile                     string
 	Provider                    string
 	Namespace                   string
+	Controller                  string
 	IsDeploymentFlag            bool
 	IsDaemonSetFlag             bool
 	IsReplicationControllerFlag bool