We need objects as well as properties to be setup because objects inside Catalogs
are basically zsql_methods which is what is needed when we use the properties.

For example: making call to `new_erp5_catalog.sql_clear_catalog` would return
a tuple of zsql methods which are basically catalog objects.
Right now, we are copying everything from SQLCatalog to the new ERP5Catalog without
checking for any conflicts(which is why there might be some overwrite).
This is why its recommended to call the migration function only furing ERP5Site setup.
TODO: This overwriting would be fixed later on so to make the migration function
a bit more generic and use it anytime-anywhere.