updating project config to be extendable

[rpmcginty]

What's in this Change?

• I have made project config extendable (by making StageConfig and GlobalConfig overridable).

you can still just use the plain old ProjectConfig class (fully backwards compatible). but if you would like to use your own project sepcific Stage config, you can do so using the following pattern.

class MyStageServiceConfig(BaseModel):
    service_name: str


class ExtendedStageConfig(StageConfig):
    service: MyStageServiceConfig


class ExtendedProjectConfig(BaseProjectConfig[GlobalConfig, ExtendedStageConfig]):
    pass

Testing

• unit tests

[sheriferson]

I noticed get_config is not included in __all__. Is that on purpose?
I am actually using it in app.py by importing from utils, but I can see that there might be a better pattern out there.

[rpmcginty]

good catch. I will add