Fixed failing signups and made oauth settings work

Fixed the signup form so it no longer fails, and made the oauth login buttons only appear when they have been enabled in the settings.json file

config/example-settings.json

@@ -2,12 +2,12 @@
     "branding":{
         "name":"AiThingy"
     },
-    "auth_mode":"code",
+    "signup_mode":"code",
     "default_role":"none",
     "default_permissions":[
         "createChat"
     ],
-    "auth_codes":[
+    "signup_codes":[
         {
             "name":"code1",
             "code":"a1b2c3",
@@ -29,5 +29,6 @@
         "enabled":"true",
         "client_id":"client_id",
         "client_secret":"client_secret"
-    }
+    },
+    "mongo_password":"yourMongoPassword"
 }