Orkestra should use the ApplicationGroup namespace as the namespace for Argo workflows

**Is your feature request related to a problem? Please describe.**
Currently, we use always use the `orkestra` namespace to run the argo workflows. Instead of using this always, we should use the `ApplicaitonGroup` namespace and generate the workflows in that namespace. This will allow teams that have security models that separate their logic into different namespaces to use multiple application groups in different namespaces.