[sailfish-browser] Update toolbar to the new design

This doesn't contain yet double height toolbar for portrait
orientation. Double height toolbar will show title and url
for user while page is loading.

Toolbar is now animated with discrete y transition instead
of opacity animation. Logic is the same as it was previous
except the gesture threshold is cut to half.

Requires: https://github.com/tmeshkova/qtmozembed/pull/75

Setting manager is changed to singleton. Initialization happens similarly as previously, only toolbarSmall and toolbarLarge properties are exposed to the qml through Settings context property.