Farm based features

It would be nice if users could use their farm id basically wherever a node id is used now, and the action would apply to all nodes in the farm.

This can be done in a simple and backwards compatible way:

```
/sub farm 1
```

While the existing format can remain for nodes:

```
/sub 1
```

Though maybe it would be nice to *additionally* add this form:

```
/sub node 1
```