Helm chart - Allow custom extra arguments

[nicolas-laduguie]

Which component are you using?:
Helm chart

Is your feature request designed to solve a problem? If so describe the problem this feature should solve.:
At the moment, the helm chart provides ability to give extraArgs in yaml key=value format, or eventually key for arguments not requiring any value (see https://github.com/kubernetes/autoscaler/blob/1603c19e62dc46a9bb1d176624e1964d974b3ef1/charts/cluster-autoscaler/templates/deployment.yaml#L128C45-L128C54).
For some other needs, it would be beneficial to let the user provide any value as an extra argument.
For instance providing a env variable like $ENV_VAR as an extra argument would help making arguments more dynamic, loaded from configmap or secrets for instance.

Describe the solution you'd like.:

Since the extraArgs value is already templated and computed in a specific way, would be easier to create a new customArgs value that would be given as is to the command.

[adrianmoisey]

/area helm-charts

[adrianmoisey]

/area cluster-autoscaler

[omerap12]

PR submitted here: #7423