Check for mandatory fields when registring master data list

[Jean-MichelForhan-KLEE]

When getting a master data list from the store, a check is made to verify that the DtObject has defined a sort field and a display field. This means that the error appears only when trying to get the list.

As master data list needs to be registred before using them, this check could be made at that time. This would have the effect of preventing the application to start if master data list are registred incorrectly as it is currently the case when registering messages in the LocaleManager