Remove coredns config from ref-implementation

This breaks current idpbuilder by overriding the coredns configuration
which rewrites dns requests to cnoe.localhost.me to the ingress. It
appears this configuration is also generally not needed, so rather than
fix it here lets just remove it.

Signed-off-by: Greg Haynes <greg.haynes@autodesk.com>

ref-implementation/coredns.yaml

@@ -1,21 +0,0 @@
-apiVersion: argoproj.io/v1alpha1
-kind: Application
-metadata:
-  name: coredns
-  namespace: argocd
-  labels:
-    env: dev
-spec:
-  project: default
-  source:
-    repoURL: cnoe://coredns/manifests
-    targetRevision: HEAD
-    path: "."
-  destination:
-    server: "https://kubernetes.default.svc"
-    namespace: kube-system
-  syncPolicy:
-    syncOptions:
-      - CreateNamespace=true
-    automated:
-      selfHeal: true

ref-implementation/coredns/manifests/cm-coredns.yaml

@@ -1,33 +0,0 @@
-# the only purpose of this is to resolve external DNS entries such as `redesigned-bassoon-r4jjwpvv99vhx9gp-8080.app.github.dev` to a cluster IP
-# normally, `redesigned-bassoon-r4jjwpvv99vhx9gp-8080.app.github.dev` resolves to 127.0.0.1 and thus oidc endpoint configurations cannot be obtained.
-# in addition, we need to ensure traffic do not go out of cluster when not necessary.
-apiVersion: v1
-kind: ConfigMap
-metadata:
-  name: coredns
-  namespace: kube-system
-data:
-  Corefile: |
-    .:53 {
-        errors
-        health {
-           lameduck 5s
-        }
-        ready
-    
-        rewrite name cnoe.localtest.me ingress-nginx-controller.ingress-nginx.svc.cluster.local
-    
-        kubernetes cluster.local in-addr.arpa ip6.arpa {
-           pods insecure
-           fallthrough in-addr.arpa ip6.arpa
-           ttl 30
-        }
-        prometheus :9153
-        forward . /etc/resolv.conf {
-           max_concurrent 1000
-        }
-        cache 30
-        loop
-        reload
-        loadbalance
-    }