MainBoard: Routing (coprocessor power), remove one output capacitor from LDO - shared with STM

MainBoard: Mirror iLed step-down (to the bottom side)

MainBoard: Mirror motor connectors (to the bottom side) and swap signals to keep previous routing

MainBoard: Compete USB, swap VUSB_DET and BUTTON_ON, all parts on board

MainBoard: Fix USB connectors packages, add Design block backup file extensions to gitignore

MainBoardBRD: Rotate servos step-down to shorten power trace

MainBoard: Swap IN4A and IN4B, routed motors + servos

Enable c++17

Add doc for ByteFifo

Rename *Range to *Span in ByteFifo