Add support for managing user BlackBerry runtime configurations.

This does not handle adding manual runtimes yet, but only detects
runtimes from the NDK directories of the available API levels.

The BlackBerry NDK should provide a better way to detect installed
runtimes (e.g xml installation files) in order to improve
the BlackBerry runtime managemnt in Qt Creator.

Change-Id: I4f139d52352f903a27dfe4175d12b016b4ee25a9
Reviewed-by: Nicolas Arnaud-Cormos <nicolas@kdab.com>