Page- / Group-List in ui-control

### Description

Hallo,
I would like to be able to retrieve a list of all pages and groups.

```
msg.payload = "getpagelist" -> ui-control -> msg.payload = "pagelist" msg.pages=[,]
msg.payload = "getgrouplist" -> ui-control -> msg.payload = "grouplist" msg.groups=[,]
```

Thank You
Greets Thomas

### Have you provided an initial effort estimate for this issue?

I am no FlowFuse team member