1. Proposed title of this feature request

Allowing Sidecar Containers to be added to ArgoCD Deployments 

2. What is the nature and description of the request?

According to this git issue from the ArgoCD upstream: https://github.com/argoproj/argo-cd/issues/8820#issuecomment-1099247399 

argocd-cm plugins are being deprecated in favor of sidecar plugins. OpenShift GitOps currently does not allow modifications to the containers field of ArgoCD Deployments. 

(I would expect this to be at argocd.spec.repo.containers) in the crd. Because of this, sidecar containers cannot be created. 

Additionally, as stated in this git issue: https://github.com/argoproj/argo-cd/issues/8820 

The ability of argocd-cm CMP plugins can no longer use the git credentials that the repo server has access to (Worked before GitOps version 1.5.0). meaning plugins that pull from a private repo fail to authenticate. The suggested fix for this is to use sidecar containers.

3. Why does the customer need this? (List the business requirements here)

In order for plugins that pull dependencies from a private git repo, and because argocd-cm is being deprecated upstream.

4. List any affected packages or components.

OpenShift GitOps ArgoCD Custom Resource.