RSDK-9445: move generated python model out of main

[purplenicole730]

Changes:

• replaced unused ModuleInputs.ModelLowercase with new ModelSnake
• split src/main.py to be src/main.py and src/models/<modelSnake>.py
• flyby import fixes

Testing:

1. generated a Python module: Module successfully generated at temporary
2. changed do_command() to return {"hi": "nicole"}
3. ran this module on a local machine
   2025-02-06T20:13:23.519Z INFO rdk.modmanager.temporary modmanager/manager.go:1286 Registering component API and model from module {"module":"temporary","API":"rdk:component:sensor","model":"ns:temporary:hello-sensor"}
4. called sensor.do_command
sensor get_readings return value: {'hi': 'nicole'}