ClusterManager: Implements support of remote clusters.

After this change users will be able to:
* Create cluster and add/remove servers to it
* Install apps on remote cluster
* Move already installed apps between clusters
* Apps running on server being removed will auto-migrate
  to another server from that same cluster

This is achieved by:
* Installing and running minimal version of dodo on remote cluster
* Ingress-nginx is installed automatically on new clusters
* Next to nginx we run VPN client in the same pod, so that
  default cluster can establish secure communication with it
* Multiple reverse proxies are configured to get to the
  remote cluster service from ingress installed on default cluster.

Next steps:
* Support remote clusters in dodo apps (prototype ready)
* Clean up old cluster when moving app to the new one. Currently
  old cluster keeps running app pods even though no ingress can
  reach it anymore.

Change-Id: Iffc908c93416d4126a8e1c2832eae7b659cb8044
diff --git a/core/installer/cmd/dodo_app.go b/core/installer/cmd/dodo_app.go
index 2fe1697..8512691 100644
--- a/core/installer/cmd/dodo_app.go
+++ b/core/installer/cmd/dodo_app.go
@@ -201,6 +201,8 @@
 		},
 	}
 	vpnKeyGen := installer.NewHeadscaleAPIClient(dodoAppFlags.headscaleAPIAddr)
+	// TOOD(gio): implement
+	var cnc installer.ClusterNetworkConfigurator
 	s, err := welcome.NewDodoAppServer(
 		st,
 		nf,
@@ -217,6 +219,7 @@
 		nsc,
 		jc,
 		vpnKeyGen,
+		cnc,
 		env,
 		dodoAppFlags.external,
 		dodoAppFlags.fetchUsersAddr,