Add custom peripheral classes into plane code

[evinli]

For this task, we want to build up our own Python scripts to run on the plane. This includes:

• main.py: Our main entry point for all plane software
• peripherals/sensors.py: This is our hardware driver class for interfacing with the sensor board
• peripherals/radio.py: This is our hardware driver class for interfacing with the RFD900 telemetry radio
• peripherals/PADA.py: This is our class for interfacing with the PADA MCU/flight controller
• peripherals/servo.py: This is our hardware driver class for interfacing with our drop servo on the plane (for dropping the PADA)

On a high-level, that is the end-functionality we want to achieve. How you decide to split this into classes and modularize it is up to you (we can also discuss!)

1. Reads flight data over UART from sensor board and serial.writes() it to the RFD900 telemetry radio after timestamping each packet
2. Listens for commands over radio from the ground station and executes the command such as a) load prediction GPS to PADA and generate waypoints and b) drop PADA

You can refer to last year's code here.