Structure smartwatch code for multiple sensors

[BjarneS28]

Code for smartwatch sensor reading should be structured in a way that allows to easily add more sensors to both the logic as well as the UI. Create a package for health monitoring (later we will have another one for reminders), use proper classes and methods to keep different concerns separate.

[BjarneS28]

@jessica088 you can use this as a starting point: https://github.com/phpngn/UCSD-CSE-118-218-Team-H/tree/main/sensors