Proximity API

[alexandruCarp]

Pull Request Overview

This pull request adds:

• a Proximity API which provides a function that simulates a synchronous proximity reading, functions to only read a value between some thresholds (sync and async), and also functions to initiate a reading, register/ unregister a listener and check for driver existence.
• an example app which samples the proximity sensor every 2 seconds and prints the measured value.
• a fake proximity driver, for testing purposes.
• unit tests for the fake driver and for the user space library

Testing Strategy

This pull request was tested with the unit tests.

TODO or Help Wanted

Feedback is much appreciated.

Documentation Updated

• no updates are required.

[jrvanwhy]

bors r+

[bors]

Build succeeded:

• ci
• size-diff