Redesign QSSecurityFooter dialog

The dialog consists now of up to four sections: Device management,
CA certificates, Network Logging and VPN.

Also, small tweaks to the footer's coloring after the theme change of QS.

Bug: 34369166
Bug: 37492743
Test: in class QSSecurityFooterTest, which is part of "runtest systemui"

Change-Id: Ibf07a26fb6c5485a152f9d447f10c0f73acb94ba
(cherry picked from commit 0330f881)