Kazoo 2460: CDRs chunking

What about using `wh_util:join_binary/2`? Then you could have:

```
CSV = wh_util:join_binary([ID
                                          ,CallId
                                          ,CallerIdNumber
                                          ,...
                                         ], <<",">>)
```

Not sure, but may be a bit more legible, plus you wouldn't need all the `/binary` and wrapping with `()`

Just a thought