Added user connection support to systemwide branch

[Andrey Borzenkov]

I added initial user connections support on top of gokcen branch; it
is available for review here:

git://anongit.kde.org/clones/networkmanagement/borzenkov/networkmanagement
in branch systemwide

Branch is merged with current master (sans couple of latest commits).
User connections seem to work as well as displaying systemwide
connections. I have not yet really tested write support for systemwide
as our default system plugin does not support writing (not really at
least).

I had to step back from initial design which was aimed at unifying
system and user connection and fetching all of them from kded via
dbus. One issue for me is authorization - user settings service is on
system bus, so adding Update method to it need to somehow validate
user. Another - it required a bit more knowledge of (KDE) D-Bus
implementation than I have right now :) So I just added back direct
connection loading, moving it a bit up into connection widget.

User connections are actually relatively good localized - there are
just two entry points: kded and connections widget. The latter looks
absolutely ugly, but I wanted to have working prototype before
starting to clean it up.

I would like to ask whether this *may* be accepted. I am not sure how
to prepare patch got reviewboard; may be patch relative to merge point
is OK?

Regards

-andrey