use a treelist instead of tabs in configpanel

use a treelist instead of tabs in configpanel

this patch changes configpanel class,
so that instead of creating a tabpanel,
we now are a card panel which uses a treelist
to choose the active card

this changes how the panel looks:
instead of having countless tabs on the top
we now can have a nice tree structure on the left

how the items will be interpreted by the tree
is commented in www/manager6/panel/ConfigPanel.js

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>