This area is pretty much in the responsibility of the individual teams. It is not a "must" for any team to maintain a web site. But it is highly recommended. To be more specific: it is even recommendable to have two web sites: one for internal use of the translation team and one for the KDE users the individual team is translating for. As a matter of course, both sites will be created in the language of the respective team. And both sites can also be just one if the team prefers it that way.
As already stated in the intro of this HOWTO, you can get the web space for an internal team site from the KDE project. It will be located at l10n.kde.org/teams/$LANG/ .
Normally you would use this kind of space for internal announcements, to-do lists, overviews of who is doing what, Howtos, style guides, lists of standard translations and a lot of other things related to the "infrastructure" of your team. In most cases, together with a mailing list such a team site pretty much is your "infrastructure".