fix #5734: provide missing methods for Proxmox.Utils for mobile ui

fix #5734: provide missing methods for Proxmox.Utils for mobile ui

since the mobile ui shares the Utils code with the desktop web ui, (but
not the proxmox-widget-toolkit) all methods used in constructors, etc.
there must be available in the mobile ui too.

We don't have any notification configuration options in the mobile ui,
and AFAIK we don't plan to add those there, so we can just implement
stub functions. This way the Utils constructor can proceed without
errors, fixing loading the mobile ui.

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