qbs project files: Fix some dependency exports.

Change-Id: I7049fcaab77639c17c4d0e74f7d9360a80fafcaa
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Move some functions out of defaults.js and make them project properties.

The one that is left is the only one that's actually a function taking
real input.
This saves a number of includes.

Change-Id: I77e777bbf6ed7ed4086f9a40de4dc3dd8c91a7af
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>