Update service-deployment HPA metrics (closes #202)

[ianarsenault]

This PR updates service-deployment helm chart to not be fixed to just CPU based autoscaling.

• Updated hpa template to allow passing in metrics instead of just average target utilization for CPU

helm template service-deployment \
  --set 'hpa.metrics[0].type=Resource' \
  --set 'hpa.metrics[0].resource.name=memory' \
  --set 'hpa.metrics[0].resource.target.type=Utilization' \
  --set 'hpa.metrics[0].resource.target.averageUtilization=75' \
  --set 'hpa.metrics[1].type=Resource' \
  --set 'hpa.metrics[1].resource.name=cpu' \
  --set 'hpa.metrics[1].resource.target.type=Utilization' \
  --set 'hpa.metrics[1].resource.target.averageUtilization=75'
  
 
---
# Source: service-deployment/templates/hpa.yaml
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: release-name
  labels:
    helm.sh/chart: service-deployment-0.21.0
    app.kubernetes.io/version: "0.21.0"
    app.kubernetes.io/managed-by: Helm
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: release-name
  minReplicas: 1
  maxReplicas: 20
  metrics:
    - resource:
        name: memory
        target:
          averageUtilization: 75
          type: Utilization
      type: Resource
    - resource:
        name: cpu
        target:
          averageUtilization: 75
          type: Utilization
      type: Resource
  behavior:
    {}