create-app: fix default backend listen config and comments

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/create-app/templates/default-app/app-config.production.yaml

@@ -9,14 +9,9 @@ backend:
   # callers. When its value is "http://localhost:7007", it's strictly private
   # and can't be reached by others.
   baseUrl: http://localhost:7007
-  listen:
-    port: 7007
-    # The following host directive binds to all IPv4 interfaces when its value
-    # is "0.0.0.0". This is the most permissive setting. The right value depends
-    # on your specific deployment. If you remove the host line entirely, the
-    # backend will bind on the interface that corresponds to the backend.baseUrl
-    # hostname.
-    host: 0.0.0.0
+  # The listener can also be expressed as a single <host>:<port> string. In this case we bind to
+  # all interfaces, the most permissive setting. The right value depends on your specific deployment.
+  listen: ':7007'
 
   # config options: https://node-postgres.com/api/client
   database:

packages/create-app/templates/default-app/app-config.yaml.hbs

@@ -15,9 +15,8 @@ backend:
   baseUrl: http://localhost:7007
   listen:
     port: 7007
-    # Uncomment the following host directive to bind to all IPv4 interfaces and
-    # not just the baseUrl hostname.
-    # host: 0.0.0.0
+    # Uncomment the following host directive to bind to specific interfaces
+    # host: 127.0.0.1
   csp:
     connect-src: ["'self'", 'http:', 'https:']
     # Content-Security-Policy directives follow the Helmet format: https://helmetjs.github.io/#reference