Description
As a follow-up to the initial blueprint implementation under PR #4699 , this feature request is to refactor the blueprint to use variables for key configuration parameters, specifically machine_type.

This suggestion, originally made by @samskillman, will allow us to use the same blueprint for different accelerator types (e.g., A3, G4) by simply changing the input variables.

Motivation
The primary motivation is to reduce the number of blueprints we need to create and maintain. Currently, supporting a new machine type would require duplicating the entire blueprint with minor changes. Parameterizing these core values will lead to a more generic, reusable, and maintainable blueprint.

Proposed Changes

• Convert the hardcoded machine_type attribute to an input variable.
• Update documentation (e.g., README.md) to reflect the new variables and provide examples.