Allow operator shelves to contain grouped apps.

r? @diox @ngokevin 

I have a few tests failing locally, but I'm pretty sure it's an ES misconfiguration and not an actual problem. I'll see what CI thinks.
The `feed_collections` isn't good. I see this:
```
                    "group_apps": {
                        "dynamic": "true",
                        "properties": {
                            "393012": {
                                "type": "long"
                            },
                            "393038": {
                                "type": "long"
                            },
                            "393047": {
                                "type": "long"
                            },
                            "393059": {
                                "type": "long"
                            }
                        }
                    },
```

We shouldn't be having each app id be the key here. We should have the key be something like "apps" and the value be the list of apps.

The `group_names` looks good and could easily be specified as a `lang`=>`string` in the mapping.