Warning / Info icon added for the VPN Preference

Within the Provider Model, we would like to show a warning icon if the
user is detected to be using an insecure vpn type. This adds an icon for
that warning, and an imageview containing that layout to settings

Icon: https://screenshot.googleplex.com/644ZsGtVDp6hgZq
Bug: 176821216
Test: atest SettingsUnitTests
Change-Id: I59fd7765876fe58fe2c55929f711c04a45abbe09