Rework MPS limit normalization

[elezar]

With this change we always specify limits in terms of UUIDs
when passing these to the MPS control daemon. We also check for
valid indices.

Using this we see:

spec:
  containers:
  - args:
    - |-
      set -e
      rm -f /var/log/nvidia-mps/startup.log

      nvidia-cuda-mps-control -d
      echo set_default_active_thread_percentage 50 | nvidia-cuda-mps-control
      echo set_default_device_pinned_mem_limit GPU-f22fb098-d1b3-3806-2655-ba25f02229c1 10240M | nvidia-cuda-mps-control

      echo "startup complete" > /var/log/nvidia-mps/startup.log

      tail -n +1 -f /var/log/nvidia-mps/control.log
    command:
    - chroot
    - /driver-root
    - sh
    - -c
    env:
    - name: CUDA_VISIBLE_DEVICES
      value: GPU-f22fb098-d1b3-3806-2655-ba25f02229c1

Assuming the following claim parameters:

---
apiVersion: gpu.resource.nvidia.com/v1alpha1
kind: GpuClaimParameters
metadata:
  namespace: sharing-demo
  name: gpu-mps-sharing
spec:
  sharing:
    strategy: MPS
    mpsConfig:
      defaultActiveThreadPercentage: 50
      defaultPinnedDeviceMemoryLimit: 10Gi

and

spec:
  containers:
  - args:
    - |-
      set -e
      rm -f /var/log/nvidia-mps/startup.log

      nvidia-cuda-mps-control -d
      echo set_default_active_thread_percentage 50 | nvidia-cuda-mps-control
      echo set_default_device_pinned_mem_limit GPU-3109fa37-4445-73c7-b695-1b5a4d13f58e 5120M | nvidia-cuda-mps-control

      echo "startup complete" > /var/log/nvidia-mps/startup.log

      tail -n +1 -f /var/log/nvidia-mps/control.log
    command:
    - chroot
    - /driver-root
    - sh
    - -c
    env:
    - name: CUDA_VISIBLE_DEVICES
      value: GPU-3109fa37-4445-73c7-b695-1b5a4d13f58e

when using:

---
apiVersion: gpu.resource.nvidia.com/v1alpha1
kind: GpuClaimParameters
metadata:
  namespace: sharing-demo
  name: gpu-mps-sharing
spec:
  sharing:
    strategy: MPS
    mpsConfig:
      defaultActiveThreadPercentage: 50
      defaultPinnedDeviceMemoryLimit: 10Gi
      defaultPerDevicePinnedMemoryLimit:
         0: 5Gi