Modules can now call:
env.module_add_dependencies(name: str, deps: list, optional: bool)
To add required or optional dependencies during the "can_build" step.
Required dependencies will be checked and the module will be not be
enabled when they are missing, printing a warning to notify the user.
* Changed to use the same stages as extensions.
* Makes the initialization more coherent, helping solve problems due to lack of stages.
* Makes it easier to port between module and extension.
* removed the DRIVER initialization level (no longer needed).
