Consolidate evolver config and calibration config files

evolver_config.json contains: 

```json
{"ip": "192.168.1.37", "mac": "b8:27:eb:34:55:8a", "deviceName": "evolver-darwin"}
```

calibrations.json contains: 

```json
{"activeCalibration": {"temp": {"filename": "sample_tempcal.txt"}, "od": {"filename": "sample_odcal.txt"}}}
```

Could be consolidated into one file to simplify file structure