Flight Computer harware agnostic

This tag marks the last commit before a refactor.
The different architecture proved effective in allowing different hardware targets (including std targets).
The ground-station is still under development with a functional back-end, but no frontend.
The simulator provides a rough implementation of a physics engine and simulated peripherals that connect the physics engine to the simulator.

This next refactoring will implement error and event tracking as part of the flight computer, and make the code more structured and readable. Peripheral traits should be implemented in the FC behind features, to minimize unused flash space.
The simulator should become more modular, allowing SITL and HITL, by using the ground station backend (postcard) as a forwarder to comunicate with the FC, instead of library function calls, detaching the simulator from the FC.
Emphasis will be given on the documentation side of all libraries. As such, the public API will be documented, and a greater focus will be given into using core traits. Additionally, sensor data will be simplified, and greater focus will be given to a "state", preparing this next iteration for state estimators.
The simulator should sonely communicate to the ground-station, allowing SITL and HITL seamlessly (as the only dependency for this becomes the FC - Groundstation connection).
Further integration with xtask is required.

This new refactor aims to restructure the FC and simulator to prioritize development under SITL!
The following refactor / release should add ESP support and hardware testing.