Update WireGuard to match NetworkManager 1.16 interface

Summary:
In NetworkManager 1.16 handling of WireGuard interfaces was changed
from a VPN add-on to a core interface type with a different API. This
plasma-nm update is intended to match that change including (but not
limited to) moving address specification to the IPv4 and IPv6 tabs and
the ability to add multiple Peers to an interface.

BUG: 405501

Reviewers: jgrulich, #vdg, ngraham

Reviewed By: jgrulich, #vdg, ngraham

Subscribers: ngraham, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D20930