petri: backend agnostic vtl2 settings configuration

[tjones60]

Move some stuff around so configuring VTL2 settings is done the same way across both backends.

[Copilot]

Pull request overview

This PR refactors VTL2 (Virtual Trust Level 2) settings configuration to be backend-agnostic, allowing both OpenVMM and Hyper-V backends to configure VTL2 settings using the same unified API. This improves consistency and maintainability across the petri test framework.

Key changes:

• Simplified Vtl2StorageControllerBuilder API by replacing scsi() and with_protocol() with a single new(protocol) constructor
• Moved VTL2 settings from backend-specific resources to a shared PetriVmRuntimeConfig structure
• Unified VTL2 settings modification through vm.modify_vtl2_settings() instead of backend-specific methods

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
petri/src/vm/vtl2_settings.rs	Simplified Vtl2StorageControllerBuilder API with unified constructor
petri/src/vm/mod.rs	Added PetriVmRuntimeConfig, unified VTL2 settings configuration, and runtime modification methods
petri/src/vm/openvmm/mod.rs	Moved VTL2 settings from resources to config, implemented default_vtl2_settings() trait method
petri/src/vm/openvmm/start.rs	Updated to return PetriVmRuntimeConfig and apply VTL2 settings consistently
petri/src/vm/openvmm/runtime.rs	Changed VTL2 settings modification from stateful to stateless set_vtl2_settings()
petri/src/vm/openvmm/modify.rs	Updated to use unified VTL2 settings location
petri/src/vm/openvmm/construct.rs	Updated VTL2 storage controller builder usage
petri/src/vm/hyperv/mod.rs	Removed backend-specific VTL2 config methods, implemented unified trait methods
vmm_tests/vmm_tests/tests/tests/x86_64/storage.rs	Updated tests to use new unified VTL2 settings API
vmm_tests/vmm_tests/tests/tests/x86_64/openhcl_linux_direct.rs	Updated to use new Vtl2StorageControllerBuilder::new() API
vmm_tests/vmm_tests/tests/tests/multiarch/openhcl_servicing.rs	Updated to use new Vtl2StorageControllerBuilder::new() API

[github-actions]

At least one Petri test failed.

[mattkur]

So I understand the intent ... will this eventually include things like disks? (a disk can be added/removed at runtime, but not a controller)

[tjones60]

Yes exactly. In my storage PR #2551 I added the storage controllers here. Also, I do eventually want to separate the creation from the start, so I think it is fine to include things here that can only change when the VM is off, and the PetriVm struct will enforce what is allowed when the VM is running vs stopped (this struct won't be directly exposed to the test).