[Mediawiki-i18n] moment.js and i18n messages

[Fòram na Gàidhlig]

In the CLDR "x ago" are full strings. They will have a reason to have
done that.

So, something like

* a moment ago
* $1 {{PLURAL:$1|second|seconds}} ago
* $1 {{PLURAL:$1|minute|minutes}} ago

and

Edited $1

with an approproate translators comment sounds best to me, and the time
strings should definitely be in core and translated ony once across all
of Mediawiki.

Maybe you can even take the "X ago" part directly from the CLDR?