Extract as constants all the controlplane env vars

[mlavacca]

Problem Statement

We use several environment variables to configure the controlplane, and all of them are hardcoded in this function body.
We need to extract them as constants into the /internal/consts/controlplane.go file and reference them.
Furthermore, as we re-use the same code block many times, we should create an helper and pass the proper env var to perform the needed checks and assignment

if _, isOverrideDisabled := dontOverride["CONTROLLER_PUBLISH_SERVICE"]; !isOverrideDisabled {
  publishServiceNN := dataplaneServiceNN(args.namespace, args.dataplaneIngressServiceName)
  if envValueByName(container.Env, "CONTROLLER_PUBLISH_SERVICE") != publishServiceNN {
    container.Env = updateEnv(container.Env, "CONTROLLER_PUBLISH_SERVICE", publishServiceNN)
    changed = true
  }
}

Acceptance Criteria

• All the above env vars are extracted into proper constants.
• the code block above is factorized as a function.