Category Picker/Manager: Key not present and untranslated lang only display the key, not the next available lang (according to the lang order of pref in Admin Center)

When a category is not translated (lots of them when you switch in EN with the file in attachment on parent jira), you do not see any more (it was the case in Jahia 5), the value of the other lang (next lang which is transalted by order of pref according to the lang rating in multlang menu in admin center).

This should be of course clearly indicated as not being the value of the current lang.

Otherwise some customers are used to use and type the category key at the place of the value. This is often the case in large companies where you have some fixed accounting plan or similar policies. End-users finally know by heart the key code of such or such classification axis. This was then a requirement asked for Jahai 5 for the Geneva Counties project (search either by key or by value).

The key of the category is now only indicated if there is no value in the current lang. Moreover it is impossible to use the search field in order to lookup a category according to its key.

We should rather list something similar to (should be quite the same in Jahia 5):

(key) value

or if value is not translated:

(key) N/A - FR: value