Provide proxies for I2C and SPI

[rsbohn]

basic.Adafruit_BME280 provides a simplified interface to the device.
advanced.Adafruit_BME280 provides additional functionality.

Each of the above classes has subclasses for _I2C and _SPI busses.
The user will instantiate the appropriate subclass based on their connection.
basic.Adafruit_BME280_I2C or basic.Adafruit_BME280_SPI for example.

pylint complains that there is duplicate code between the basic and advanced implementations. The code to instantiate, read, and write to the device
is duplicated in both implementations.

This pull request provides a single implementation for I2C and for SPI.
To use *_Impl I added a parameter to the init method
to set the selected implementation class.

Questions:

• Is 'protocol.py' the right name for the file containing the different bus-specific implementations?
• Is there a better name than *_Impl?
• Is this a proxy or perhaps a delegate? The data attribute in Adafruit_BME280 should be named accordingly.

This work was part of the CircuitPythonDay2022 Sprint.

[FoamyGuy]

This is looking pretty good to me. Looked over the code, but don't have a sensor to use for testing.

Is 'protocol.py' the right name for the file containing the different bus-specific implementations?

I think protocol.py is a good name for it. It could perhaps be implementations.py but I'm not really sure that is any more clear so not sure if it's better really. I can't think of anything that seems definitely better than protocol.py

Is there a better name than *_Impl?

I can't think of anything better than Impl, I think implementation conveys the idea of what it's doing well. Open to input from others though.

[FoamyGuy]

I had another look over this, and does look good to me.

I'll wait and see if we can get someone to test it with hardware. I can try to get a sensor after a bit if no one tries it out first.

[FoamyGuy]

I tested this successfully with

Adafruit CircuitPython 8.0.0-beta.0 on 2022-08-18; Adafruit Feather ESP32S2 with ESP32S2
Board ID:adafruit_feather_esp32s2

Using the simpletest script in the examples directory of this repo to connect via I2C and get readings from the sensor.

Thanks again for working on this Dexter.