Move search closer to mockups

Show the search bar also on the installed page, and move the
search entry signal handler to a better place.
Move search closer to the mockups

Make typing go to the search entry whenever it is visible, and
make Escape clear the entry.
Move search closer to the intended behaviour

Go back to the previous tabwhen search entry is cleared.
Avoid some double strokes
Fix up visibility of the search bar

At application start, we are calling refresh functions without
making the corresponding page current. To avoid unintended effects,
the refresh functions and their async callbacks must not change
the visibility of any shared ui elements unless the page is still
current.