Retain kura build artifacts in the CI workspace available for downloads

[mcarrer]

Retain kura build artifacts, especially Kura installers for various platforms, in the CI workspace available for downloads.

[MMaiero]

Since Build #570 Hudson build will retain the artifacts of Kura-snapshot builds. Following the list of .deb and .sh files available from the build page:

• kura_{version}_beaglebone-nn_debian_installer.deb
• kura_{version}_beaglebone_debian_installer.deb
• kura_{version}_intel-edison-nn_installer.sh
• kura_{version}_raspberry-pi-2-nn_installer.deb
• kura_{version}_raspberry-pi-2_installer.deb
• kura_{version}_raspberry-pi-bplus-nn_installer.deb
• kura_{version}_raspberry-pi-bplus_installer.deb
• kura_{version}_raspberry-pi-nn_installer.deb
• kura_{version}_raspberry-pi_installer.deb