archwiki: Switch notification mail to noreply

Change this to the noreply mail but also add a wiki tag to it so it can more easily be filtered in mail programs.

cc @archlinux/teams/wiki/admins

roles/archwiki/templates/LocalSettings.php.j2

@@ -112,7 +112,7 @@ $wgEnableEmail      = true;
 $wgEnableUserEmail  = true; # UPO
 
 $wgEmergencyContact = "webmaster@archlinux.org";
-$wgPasswordSender   = "webmaster@archlinux.org";
+$wgPasswordSender   = "noreply+wiki@archlinux.org";
 
 $wgEnotifUserTalk      = true; # UPO
 $wgEnotifWatchlist     = true; # UPO