feat(helm_chart/aws-vpc-cni): add overrideRepository images option

[QuentinBtd]

What type of PR is this?
Helm Chart feature

Which issue does this PR fix?:

No issue

What does this PR do / Why do we need it?:
Add overrideRepository to image option to override only image repositories and continue to use tag value.

It is useful if you want to use, for example, public.ecr.aws/eks/amazon-k8s-cni repository with the tag provide by the default chart values.

Testing done on this change:

I've deployed VPC CNI using the chart with these values:

init:
  image:
    overrideRepository: public.ecr.aws/eks/amazon-k8s-cni-init
nodeAgent:
  image:
    overrideRepository: public.ecr.aws/eks/aws-network-policy-agent
image:
  overrideRepository: public.ecr.aws/eks/amazon-k8s-cni

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?:

No

Does this PR introduce any user-facing change?:

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

[QuentinBtd]

👋🏻 @jaydeokar

[jaydeokar]

lgtm