Improve BtTestUI device and service discovery output

This was recently used to debug Androids buggy discovery code.

Change-Id: I6c3eca85a650d6fbb853d2cfc8ee73b434b5e7a9
Reviewed-by: Nedim Hadzic <nedimhadzija@gmail.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>