KAZOO-2863 search module

I wonder, to avoid converting to/from lists, if this could be written as:

```erlang
get_end_key(Bin) ->
    Size1 = byte_size(Bin) - 1,
    <<B:Size1/binary, C>> = Bin,
    <<B/binary, (C+1)>>.
```

Maybe add a unit test as well??? :)