Cyberphys hardware doc updates

[kris-agile-hardware]

Updated hardware documentation with LED String Manager Board and Interface information and latest physical architectural diagram.

LED String Manager information is new.

The physical architecture diagram contains the following updates:

• Added USB relay board to control power to Shifter + Pedals Teensy Board
• Removed LED String Management Implementation with discrete wiring and replaced with LED String Manager Board implementation because that is how the LEDs are managed in the demonstrator
• Updated the seat vibrator implementation to match the demonstrator

[kris-agile-hardware]

@podhrmic no problem!