Create a new clear data dialog

https://bugzilla.gnome.org/show_bug.cgi?id=720113
Create a new cookies dialog

https://bugzilla.gnome.org/show_bug.cgi?id=720113
Hook up new cookies dialog to prefs dialog

https://bugzilla.gnome.org/show_bug.cgi?id=720113
Remove personal data manager

https://bugzilla.gnome.org/show_bug.cgi?id=720113