- Change Generator class to store machine name as string instead of Machine reference
- Update Generator.generators_from_flake() to only require machine name and flake
- Refactor check_vars() to accept machine name and flake instead of Machine object
- Create Machine instances only when needed for specific operations
This continues the effort to reduce dependencies on the Machine class,
making the codebase more modular and easier to refactor.
Replace all calls to machine.vars_generators() with direct calls to
Generator.generators_from_flake() to make the dependency more explicit
and remove unnecessary indirection.
This reduces coupling to the Machine class, making the codebase more
modular and easier to refactor in the future.
