Editor: allow to switch yaml content from values in quotes to values without quotes

Currently cluster resources are displayed as yaml that has values in quotes:
```yaml
app.kubernetes.io/name: "openshift-quickstart"
```

Yaml values can be provided without quotes though:
```yaml
app.kubernetes.io/name: openshift-quickstart
```

It would be handy if there was a way to switch from one display mode to the other one in the tooldbar of the editor.
