Implement Kalman Filter in STM32 version

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Implement the Kalman Filter class as well as the basic setup found in Rust/main.rs

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Finished large portion of implementation

Still left todo:

• use a timer to actually get dt of each iteration
• use mbed threads to run IMU and baro separately (GPS in the future)
• add GPS wrapper class once implemted

[explosion33]

Added a timer for sync version
setup a working async version

todo:

• add GPS struct data gathering into the filter
• refactor the entire KalmanFilter class

[explosion33]

Kalman Filter has been refactored, all that's left to do is test the GPS