[Task] patina_boot: Implement BootOptionDiscovery component

[kat-perez]

Description

Implement the BootOptionDiscovery component as outlined in the Boot Orchestration RFC.

Requirements

• Read Boot#### variables containing EFI_LOAD_OPTION structures
• Read BootOrder variable to determine boot attempt sequence
• Provide discovered options to BootOrchestrator via Config<BootOptions>
• Depend on RuntimeVariableServices

Context

This enables the UEFI-compliant boot path. Currently, platforms must provide hardcoded device paths via Config<BootOptions>. With this component, platforms can use standard UEFI boot variables.

Related

• RFC: Boot Orchestration (RFC: Boot Orchestration Component #1013)
• PR: patina_boot crate ([feature/patina-boot] patina_boot: Add boot orchestration crate #1225)