Implement Device Authorization

[StevonStevoff]

We need to implement authorization for the hardware devices.

This will involve:

• [x] Update device database model to store token
• [x] Code to generate device JWT
• [x] Update registration route to create token for first time
• [x] Update schema to supply token from get request
• [x] Route to refresh token
• [x] Update plant_data route to require this token as authorization
• [x] Code to decode token and retrieve device ID