AO-91 Add ClusterAgentInjectors to helm chart

[gamingrobot]

• Add ClusterAgentInjectors to helm chart
• Add namespaceLabelSelector for support ClusterAgentInjectors in helm chart
• Create ClusterAgentInjectors by default in helm chart
• Remove lookupNamespaces, replaced by namespaces: '*' when using useClusterAgentInjectors: true

Example template output

# Source: contrast-agent-operator/templates/agent-injectors.yaml.tpl
apiVersion: agents.contrastsecurity.com/v1beta1
kind: ClusterAgentInjector
metadata:
  name: contrast-flex-injector
  namespace: 'contrast-agent-operator'
spec:
  namespaces:
    - default
  namespaceLabelSelector:
    - name: namespacelabel
      value: labelvalue
  template:
    spec:
      type: flex
      selector:
        labels:
          - name: contrast-agent
            value: flex

[andersonshatch]

When you do a helm upgrade this will fail because the CRD is not present.
Maybe we could check if it exists and print some guidance at that point?
That would likely bring back a call to lookup and that doesn't work in every tool though, maybe it's just some migration docs, presuming this will be a new major version?

[gamingrobot]

I tried to move the CRDs into the templates directory but this doesn't work because helm templates/validates before helm hooks are called so even if the CRDs are labeled with pre-install/pre-upgrade the template step fails with "ensure CRDs are installed first". We have https://docs.contrastsecurity.com/en/helm-upgrades.html for upgrade instructions (kubectl replace should be kubectl apply though). There is a proposal to handle this better in helm 4, another option is possibly having the CRDs as a subchart but that has its own issues.