Maybe we can have a dummy start_periodic_measurement() function

SCD4x library has a function:
```
def start_periodic_measurement(self):
"""Put sensor into working mode, about 5s per measurement"""
self._send_command(_SCD4X_STARTPERIODICMEASUREMENT)
```

When porting code from SCD4x to SCD30 you have to wonder about this.
Maybe we could have a dummy function that has that name but does nothing:
```
def start_periodic_measurement(self):
"""Dummy function for forward compatibility with SCD4x library"""
pass
```

This would permit the same code (almost) to work on both kind of sensor.

Locate the SCD30 library class and its public sensor-control methods, then compare the SCD4x start_periodic_measurement() interface shown in the issue. Done means SCD30 exposes the same callable for forward-compatible code without initiating an additional sensor command; run the library's existing tests or basic examples if available.

Written by the indexing model from the issue text.