Merging ub-launcher3-qt-dev, build 5596239

Test: Manual

Bug:118757588 P1 Define launcher grid and smartspace layout for Grid style
Bug:130759508 P2 update the button style on Preview Book cover card
Bug:132726773 P2 Theme Picker selected theme (check mark is too small)
Bug:132810518 P2 Theme picker: Bottom tap text and box have off color values.
Bug:132909772 P3 ThemePicker crashes if OverlayManager is not available
Change-Id: I19ffc2805365a46cf7031d5ac3160ae869668117