Build stub package, which prevent some real package get installed. This
of course make some functionalities unusable, but this is a spirit of
minimal template - make it as featureless as possible.
Set TEMPLATE_FLAVOR variable to select template to build. That type will
be appended to template name.
Actual configuration can vary on template distribution, but generally
config files with suffix "_${TEMPLATE_FLAVOR}" will be used.
The whole build process is started as root (check Makefile), so there is
no need for additional sudo. This makes some things much simpler
(for example appending to some files).
Without chown, normal user cannot remove it (in next
prepare-repo-template). Also fix prepare-repo-template to clean only
current repo, not all of them.
