oidc: set a refresh token ttl to avoid warning

oidc-provider NOTICE: default ttl.RefreshToken function called, you SHOULD change it in order to define the expiration for RefreshToken artifacts.

src/oidc.js

@@ -890,7 +890,8 @@ async function start() {
             IdToken: 3600, // 1 hour
             Grant: 1209600, // 14 days
             Session: 1209600, // 14 days
-            Interaction: 3600 // 1 hour
+            Interaction: 3600, // 1 hour
+            RefreshToken: 1209600 // 14 days
         }
     };