add test to verify cni-metrics-helper puts metrics to CW

[abhipth]

Adds metrics helper test which does the following.

• Installs the metric helper using local helm chart.
• Adds permission to the node instance role to put metrics to CW.
• Verifies one of the metrics is published to CW.

What type of PR is this?
Integration test

Which issue does this PR fix:
NA

What does this PR do / Why do we need it:
Add missing integration test for CNI Metrics Helper

If an issue # is not available please add repro steps and logs from IPAMD/CNI showing the issue:
NA

Testing done on this change:

Running Suite: CNI Metrics Helper Test Suite
============================================
Random Seed: 1620751492
Will run 1 of 1 specs

STEP: creating the CNIMetricsHelperPolicy policy
STEP: getting the node instance profile
STEP: getting the nodegroup name and instance profile
STEP: getting the node instance role
STEP: attaching policy to the node IAM role
STEP: attaching the node instance role
STEP: updating the aws-nodes to restart the metric count
STEP: getting the aws-node daemon set in namesapce kube-system
STEP: setting the environment variables on the ds to map[SOME_NON_EXISTENT_VAR:0]
STEP: updating the daemon set with new environment variable
STEP: installing cni-metrics-helper using helm
time="2021-05-11T22:16:00+05:30" level=info msg="creating 4 resource(s)" source="release_manager.go:77"
time="2021-05-11T22:16:01+05:30" level=info msg="beginning wait for 4 resources with timeout of 0s" source="release_manager.go:77"
time="2021-05-11T22:16:03+05:30" level=info msg="Deployment is not ready: kube-system/cni-metrics-helper. 0 out of 1 expected pods are ready" source="release_manager.go:77"
test cni-metrics-helper publishes metrics when a metric is updated 
  the updated metric is published to CW
  /Users/abhipth/go/src/github.com/aws/amazon-vpc-cni-k8s/test/integration-new/metrics-helper/metric_helper_test.go:44
STEP: creating test namespace
STEP: waiting for the metrics helper to publish initial metrics
STEP: creating parking pods on the targeted node group
STEP: waiting for the metrics helper to publish new metrics
data points: [{
  Maximum: 11,
  Timestamp: 2021-05-11 16:51:00 +0000 UTC,
  Unit: "Count"
} {
  Maximum: 1,
  Timestamp: 2021-05-11 16:47:00 +0000 UTC,
  Unit: "Count"
} {
  Maximum: 1,
  Timestamp: 2021-05-11 16:48:00 +0000 UTC,
  Unit: "Count"
} {
  Maximum: 1,
  Timestamp: 2021-05-11 16:49:00 +0000 UTC,
  Unit: "Count"
} {
  Maximum: 11,
  Timestamp: 2021-05-11 16:50:00 +0000 UTC,
  Unit: "Count"
}]STEP: validating at least 2 metrics are published to CloudWatch
STEP: validating the addReqCount increased on the node after a deployment is created
STEP: deleting test namespace

• [SLOW TEST:374.862 seconds]
test cni-metrics-helper publishes metrics
/Users/abhipth/go/src/github.com/aws/amazon-vpc-cni-k8s/test/integration-new/metrics-helper/metric_helper_test.go:29
  when a metric is updated
  /Users/abhipth/go/src/github.com/aws/amazon-vpc-cni-k8s/test/integration-new/metrics-helper/metric_helper_test.go:43
    the updated metric is published to CW
    /Users/abhipth/go/src/github.com/aws/amazon-vpc-cni-k8s/test/integration-new/metrics-helper/metric_helper_test.go:44
------------------------------
STEP: getting the aws-node daemon set in namesapce kube-system
STEP: setting the environment variables on the ds to map[SOME_NON_EXISTENT_VAR:{}]
STEP: updating the daemon set with new environment variable
STEP: detaching role policy from the node IAM Role
STEP: deleting the CNIMetricsHelperPolicy policy
STEP: uninstalling cni-metrics-helper using helm
time="2021-05-11T22:23:11+05:30" level=info msg="uninstall: Deleting cni-metrics-helper" source="release_manager.go:77"
time="2021-05-11T22:23:15+05:30" level=info msg="Starting delete for \"cni-metrics-helper\" Deployment" source="release_manager.go:77"
time="2021-05-11T22:23:15+05:30" level=info msg="Starting delete for \"cni-metrics-helper\" ClusterRoleBinding" source="release_manager.go:77"
time="2021-05-11T22:23:15+05:30" level=info msg="Starting delete for \"cni-metrics-helper\" ClusterRole" source="release_manager.go:77"
time="2021-05-11T22:23:15+05:30" level=info msg="Starting delete for \"cni-metrics-helper\" ServiceAccount" source="release_manager.go:77"
time="2021-05-11T22:23:16+05:30" level=info msg="purge requested for cni-metrics-helper" source="release_manager.go:77"

Ran 1 of 1 Specs in 495.397 seconds
SUCCESS! -- 1 Passed | 0 Failed | 0 Pending | 0 Skipped
PASS

Ginkgo ran 1 suite in 8m24.614778264s
Test Suite Passed

Automation added to e2e:
NA

Will this break upgrades or downgrades. Has updating a running cluster been tested?:
No

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

Does this PR introduce any user-facing change?:
No

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