Automatic update checking/notification if new version is available

[190nm]

Would be nice to have for mods that get updates, because otherwise you might get people using older versions because they dont know a newer one is available.

I suggest having a one time pop-up that asks if a user wants to download an available update. Then adding a symbol in the "Downloadable mods" tab in case they decline it for now, and then highlighting/ marking the one in the list that has an update.

It should be handled in such a way where the user is offered to have the update done for them automatically, but isn't forced into getting the new version.