This implements an autocomplete engine inside LibWebView, to replace the
engine currently used by Qt. Whereas Qt uses the Qt Network framework to
perform autocomplete requests, LibWebView uses RequestServer. This moves
downloading this untrusted data out of the browser process.
This patch only implements the persisted settings and their UI. It does
not integrate this engine into the browser UI.
The idea with the UI here is that it will serve as a generic component
for all site settings, such as autoplay, notifications, etc. When the
site settings dialog is opened, it is filled with the requested setting
data, and messages sent to the browser process are based on the setting.
This patch only implements the UI and persisted settings. It does not
apply autoplay changes to the WebContent process.
