Add resources config option to cni metrics helper

[jcogilvie]

What type of PR is this?
feature

Which issue does this PR fix:
#2140

What does this PR do / Why do we need it:
Adds an option to set resources in the cni metrics helper helm chart

Testing done on this change:

• helm template run against the cni metrics helper chart with a values file containing:

resources:
  requests:
    memory: 256Mi
    cpu: 10m
  limits:
    memory: 512Mi
    cpu: 50m

i.e. helm template ./charts/cni-metrics-helper --values=test-resources.yaml --debug

• Visually inspected that the resources are correct:

---
# Source: cni-metrics-helper/templates/deployment.yaml
kind: Deployment
apiVersion: apps/v1
metadata:
  name: cni-metrics-helper
  namespace: default
  labels:
    k8s-app: cni-metrics-helper
spec:
  selector:
    matchLabels:
      k8s-app: cni-metrics-helper
  template:
    metadata:
      labels:
        k8s-app: cni-metrics-helper
    spec:
      containers:
      - env:
        - name: AWS_CLUSTER_ID
          value: ""
        - name: USE_CLOUDWATCH
          value: "true"
        resources:
          limits:
            cpu: 50m
            memory: 512Mi
          requests:
            cpu: 10m
            memory: 256Mi
        name: cni-metrics-helper
        image: "602401143452.dkr.ecr.us-west-2.amazonaws.com/cni-metrics-helper:v1.11.4"
      serviceAccountName: cni-metrics-helper

• applied the chart to my running cluster (eks 1.22)

Will this PR introduce any new dependencies?:
No

Will this break upgrades or downgrades. Has updating a running cluster been tested?:
No; tested an upgrade and it worked fine.

Does this change require updates to the CNI daemonset config files to work?:
No

Does this PR introduce any user-facing change?:
Yes

Added `resources` block to `cni-metrics-helper` helm chart

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[jdn5126]

@jcogilvie these changes conceptually look good to me. My only comment is that for resources, we should either have default values to render or not render the field when it is empty.