Why
ApplicationSet is merged to ArgoCD repo (GITOPS-1621). ArgoCD Operator needs to be updated accordingly

Acceptance Criteria

• Updated argocd operator with changes associated with moving ApplicationSet to Argo cd
• Since the ApplicationSet controller is no longer an 'optional' component of Argo CD, we should probably assume that the user wants it to be installed.
• So, if they create an ArgoCD k8s resource, and the ApplicationSet field is empty (nil), we should still create the ApplicationSet controller. This is different from the current logic, where if this field is empty, the ApplicationSet controller is not deployed.
• This behaviour is similar to other essential components in Argo CD, like Server/RepoServer/Controller/Dex, where we just assume that the user wants them installed (and don't give them the option of not installing them, via the ArgoCD CR).
• If we still want to give users the ability to disable the ApplicationSet controller, we could add a 'Disabled bool'  to ArgoCDApplicationSet
• Update e2e tests and documentation.