base

Use unbundled QSB for global search

This obsoletes the following:
- The need to run SearchDialog in the system process.
- The global search mode code in SearchDialog.
- The GlobalSearch package.
- The search widget built into Launcher.

I will remove these in future changes.

Change-Id: I154386b1d6be73cfeab8376b6959a1dc5483e5f0