Add support for application namespaces

[tongpu]

Is your feature request related to a problem? Please describe.
In argoproj/argo-cd#9755 Argo CD gained support for pulling in Application from outside of the namespace Argo CD is being deployed.

Describe the solution you'd like
As this feature will be added to Argo CD 2.5 I would be happy if argocd-operator would be able to support this parameter.

[iam-veeramalla]

@ishitasequeira is already working on this one. Thanks for raising the enhancement @tongpu

[Gentoli]

If there is spec.controller.extraCommandArgs, this config would work:

apiVersion: argoproj.io/v1alpha1
kind: ArgoCD
metadata:
  name: example-argocd
  labels:
    example: server
spec:
  resourceTrackingMethod: annotation+label
  controller:
   # Does not exists 
    extraCommandArgs:
      - '--application-namespaces=*'
  server:
    extraCommandArgs:
      - '--application-namespaces=*'

This will allow the user to use new features before they are supported by the operator.

I also see --application-namespaces is generated from spec.sourceNamespaces, but setting it to ["*"] will cause this error when reconciling Role(?):

1.6831749006287725e+09	ERROR	controller.argocd	Reconciler error	{"reconciler group": "argoproj.io", "reconciler kind": "ArgoCD", "name": "app", "namespace": "argocd", "error": "Namespace \"*\" not found"}

My current workaround is to disable the operator...

[timurgaleev]

is there any news here? :)

[mbaeuerle]

This feature seems to be already implemented and documented here, at least it works in my case.
https://argocd-operator.readthedocs.io/en/latest/usage/apps-in-any-namespace/