Add support for fortisslvpn

Summary:
This adds support for Fortigate SSL VPN which has been added recently to NM [1]. There is also a
bug 355079 opened for missing support.

[1] - https://blogs.gnome.org/lkundrak/2015/09/24/fortigate-ssl-vpn-support-added-to-networkmanager/

Reviewers: lvsouza, mbriza

Reviewed By: mbriza

Subscribers: mbriza, christiangonzalez, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D6189