Integrate conductor graceful shutdown and drain functionality into ironic-operator lifecycle management

Description:

After backporting conductor graceful shutdown and drain capabilities from upstream Ironic, integrate the graceful shutdown into the ironic-operator to ensure conductor pods shutdown gracefully without interrupting in-progress operations.

Acceptance Criteria:

• Expose terminationGracePeriodSeconds as part of the conductor CR template with an opinionated default (propose that 120s is appropriate)
• Propagate this terminationGracePeriodSeconds value to conductor pods, and to conductor ironic.conf [DEFAULT]graceful_shutdown_timeout
• Document timeout considerations and tuning parameters

Technical Context:

• The upgrade release notes for the graceful shutdown support 
• Controller: `controllers/ironicconductor_controller.go`
• Current hard-coded graceful termination timeout
• Affects: IronicConductor StatefulSet configuration
• Pod lifecycle: terminationGracePeriodSeconds
• Dependencies: Requires OSPRH-22299  (backported graceful shutdown code) to be complete