Lock button and infobar code should be in FirewallPanel.vala

Currently, a lot of the code that handles the InfoBar and lock button for the Firewall page are in Plug.vala. Considering the re-design where each view now has its own space and the InfoBar doesn't go right across the top of the window anymore, it makes more sense to try and move this into FirewallPanel.vala and have each panel handle polkit requests where needed.

Launchpad Details: [#LP1668384](https://bugs.launchpad.net/bugs/1668384) David Hewitt - 2017-02-27 20:02:15 +0000