cni-metrics-helper add podAnnotation value

[prysmakou]

What type of PR is this?

feature
cni-metrics-helper add deployment.podAnnotation value

Which issue does this PR fix:
N/A

What does this PR do / Why do we need it:
Allows to add arbitrary annotations to pods (eg DataDog requires specific annotation to scrap Prometheus metrics)

Testing done on this change:
manual deploy

Will this PR introduce any new dependencies?:
No

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?:
It changes the deployment/daemonset

Does this PR introduce any user-facing change?:
It introduces a new parameter in cni-metrics-helper helm chart (with a default value {} )

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

[jdn5126]

Thanks for the contribution @prysmakou! Let's follow the example set by the aws-vpc-cni chart: https://github.com/aws/amazon-vpc-cni-k8s/blob/master/charts/aws-vpc-cni/values.yaml#L117 and https://github.com/aws/amazon-vpc-cni-k8s/blob/master/charts/aws-vpc-cni/templates/daemonset.yaml#L24

Also, can you update the title and description to be cni instead of csi?