oidc: Add /api/v1/config route for determining whether to display a login button on the UI

controller/handler/cors.go

@@ -4,7 +4,11 @@ import "net/http"
 
 func DevelopmentCORS(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Access-Control-Allow-Credentials", "true")
 		w.Header().Set("Access-Control-Allow-Origin", "http://localhost:8081")
+		if r.Method == "OPTIONS" {
+			return
+		}
 		next.ServeHTTP(w, r)
 	})
 }