[FIX] web_dialog_size: Fix usage for non-admins and reduce calls (#954)

This addon had 2 problems after migrating to v11:

1. One call to backend's `ir.config_parameter.get_param` was done for
   each instantiated dialog, while the setting served for the whole
   session equally.
2. That model is now readable only by admin users, so non-admins
   couldn't use the default at all.

Fixed now.

web_dialog_size/__manifest__.py

@@ -13,9 +13,9 @@
               "Tecnativa, "
               "Amaris, "
               "Odoo Community Association (OCA)",
-    'website': "http://acsone.eu",
+    'website': "http://github.com/OCA/web",
     'category': 'web',
-    'version': '11.0.1.0.2',
+    'version': '11.0.1.0.3',
     'license': 'AGPL-3',
     'depends': [
         'web',