node.xml: the resotre roll is now called rocks-restore-roll

the package that contains the restore roll before it was called
devel-env now is is called rocks-restore-roll
nobinary: remove big binaries from git repo first take

added tree new built targets to manage downloading, verifying,
and removing external binary files (updated the 'make help' as
well)

All the logic is inside get_sources.sh which is now in charge
of downloading the various files

At built time get_sources is called automatically by the
bootstrap-function.sh so no modification is needed in the other
rolls to enable this functionality when building