Support Loading from Config

We'd like to configure RouterServer Streamer feature solely from a config if the function arguments are all literal types. Bonus: if we can use a similar schema structure returned when we call `get_stream_configurations`.

Something like:
```python
periodic_streams': {'prototome_stage_positions': {'enabled': True,
'encoding': 'pickle',
'instance': 'prototome_cd',
'callable': 'get_positions',
'args': [],
'kwds': {},
'frequency_hz': 10.0}
```

We also want to be able to configure the client via config.