Split Vulkan and Baremetal/Ethos Setup into Separate Files for Cleaner Backend Isolation

[YufengShi-dudu]

🚀 The feature, motivation and pitch

Description

Currently, setup logic for Vulkan and Baremetal/Ethos backends is done via the same script examples/arm/setup.sh. This creates unnecessary coupling between unrelated hardware backends.

For example, users working with Ethos-U may encounter Vulkan-specific configuration or code paths that are not relevant to their use case — and vice versa. This can lead to confusion, bloated dependencies, and tighter coupling in the backend setup code.

Proposal

Refactor the backend setup to isolate Vulkan and Baremetal/Ethos configurations into separate files or modules.

Source of this feature request: #12397

Alternatives

No response

Additional context

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RFC (Optional)

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cc @SS-JIA @manuelcandales @cbilgin @digantdesai