[FEATURE] Switch to HMAC Command Authentication

[Mikefly123]

Story

• As a mission operator
• I want to use more secure HMAC Command Authentication
• So that we can ensure only authorized operators are able to send commands to the satellite.

Acceptance Criteria

• Implements a system that appends a message authentication code to the end of commands from the ground station
• Have cdh.py check if the message is authentic using a shared secret
• Continue execution of the command if the authentication is correct, reject if not.
• Defend against replay attacks by through use of the packet counter

Technical Details

There may be an existing CircuitPython library we can use for this:
https://www.bing.com/search?pglt=299&q=circuitpython+hmac&cvid=80a9f37645a944e58e0bad7c37db0636&gs_lcrp=EgRlZGdlKgYIABBFGDkyBggAEEUYOTIGCAEQABhAMgYIAhAAGEAyBggDEAAYQNIBCDQwMDNqMGoxqAIAsAIA&FORM=ANNTA1&PC=U531