update date bubble to list Clocks app

- instead of managing world clocks inline, it will be better to
  offload it to the Clocks app.

https://bugzilla.gnome.org/show_bug.cgi?id=644390#c17
noise texture to be used in the message tray
search layout.
update scrollbar look to sync with gtk
remove outdated mockups
tweaks to the paginated overview
no results - (temporarily before Web provides a gateway)
more results overlay for the search page
reiterate app picker design

- use recency view by default. Same pattern we use for apps
  recently installed/used apps show up on top
- all apps shows groups. by default only utilities
  and accessories groups are created. No "management"
  happens in the overview. Eventually this will be part of
  Software. For now, the manage button can launch Alacarte
- entering groups doesn't create an overlay, but reuses the
  same single scrolled view.
use flat color for collections
use 3.6 wallpaper, alignment fixes
app picker: 3.8 changes

tweaks based on the current patchset:
- the groups aren't implemented inside the scrollable, pushing
  the first level launchers away, but as a pop over, making all
  the first level launchers insensitive. Thus they are made
  opacity: 0.3.
- the scrollable now includes the search entry
- the recent/all toggle is at the bottom of the screen:
  there is anatural flow to not finding an item and opting
  to see all entries.
make bubble align properly.

- don't just claim the bubble aligns to the grid,
  make it so.
app picker groups animation.
app picker: missing texture
false path for wallpaper
wallpaper: actually include the texture
app picker: software has a new icon