Support NVIDIADriver reconciliation without a ClusterPolicy

[karthikvetrivel]

Stacked on #2571 (kv-gpuclusterconfig-crd). This PR's diff is just the two commits below. GitHub will retarget it onto main once #2571 lands.

Summary

This PR lets the NVIDIADriver controller reconcile without a ClusterPolicy, so a GPUCluster (the DRA stack) can use operator-managed drivers standalone.

• The driver host root is now sourced via the info catalog instead of the ClusterPolicy CR. The driver renderer consumes a new InfoTypeHostRoot catalog entry rather than reading the ClusterPolicy directly, which decouples it from the gpuv1 types. When both CRs exist, the ClusterPolicy's hostPaths.rootFS takes precedence. Otherwise the GPUCluster's value is used.
• The consumer gate now accounts for both configuration CRs. If the ClusterPolicy delegates its driver (useNvidiaDriverCRD) or a GPUCluster exists, the NVIDIADriver reconciles normally. If a ClusterPolicy is present but not delegating and no GPUCluster exists, the NVIDIADriver goes disabled ("useNvidiaDriverCRD is not enabled in ClusterPolicy and no GPUCluster exists"). If neither CR exists, it goes notReady ("no ClusterPolicy or GPUCluster object found in the cluster").
• The controller now watches GPUCluster. Generation changes fan out to all NVIDIADriver instances, so creating or deleting a GPUCluster transitions NVIDIADrivers automatically without a manual poke. Operator RBAC gains get, list, and watch on gpuclusters.

Testing

There is unit coverage for the host-root sourcing and the gate transitions, plus two live validations on a single-node Tesla T4 cluster (Kubernetes 1.34, containerd 2.2).

• Standalone end-to-end: with no ClusterPolicy, a GPUCluster plus a default NVIDIADriver rolled out the driver DaemonSet. The DRA kubelet-plugin came up against the operator-installed driver root (devRoot=/run/nvidia/driver) and published its DeviceClasses and ResourceSlice. A pod with a DRA claim ran nvidia-smi against the operator-installed driver.
• Gate matrix, observed via .status.state transitions on a cluster converted from a released operator install. A ClusterPolicy that is not delegating with no GPUCluster produced disabled. A GPUCluster alone produced ready. With neither CR, the NVIDIADriver went notReady with the expected message. The ClusterPolicy plus GPUCluster coexistence path is covered by the unit tests.
• All transitions were watch-driven. Deleting or creating a GPUCluster flipped the NVIDIADriver state without manual intervention, and a single GPUCluster creation transitioned two NVIDIADriver instances at once.

[coveralls]

Coverage is 32.929% — kv-nvidiadriver-standalone into kv-gpuclusterconfig-crd. No base build found for kv-gpuclusterconfig-crd.