Add a column date added to the glossary

[psmits1567]

Currently if you are not a GTE, you cannot see when a glossary entry was added.
To keep track of new glossary verbs it would be very helpful if the column of date added is shown in the table. In that way you will get a quick view of newly added glossary verbs.

Even better would be a notification in the polyglots channel of the locale, after a new glossary verb is added.