Refactor the sensor library

[clementnuss]

Hi!

I spent some time refactoring this library as a "ressource" class:
in the src/ folder, you'll find the examples, as well as a python module tfluna.
In this module, I defined the TfLuna class, that you can use as follows :

with tfluna.TfLuna(baud_speed=115200) as tfluna:
    tfluna.get_version()
    distance,strength,temperature = tfluna.read_tfluna_data() # read values
    # etc

This makes using the sensor far easier, as the resource closing is handled by the with-resource concept, and the sensor code is centralized.

[clementnuss]

I have also created a python module here: https://pypi.org/project/tfluna-driver/
It might be simpler not to merge this PR in the end: keep this repo as example code, and point to my repo where I will continue to update the driver.
As you prefer! Best regards,
Clément

[BaitaSquirrel]

Hi clementnuss, appreciate what you've done with this. I just picked up a TF-luna so haven't gone to implement. Just curious. Is there a reason for using UART over i2c with this unit?

[clementnuss]

Hi, no reason at all. I simply reused the serial code that was already written. Feel free to implement it if you have time :)