replacements for ltsp-build-client

[Vagrant Cascadian]

In ltsp6, i'd like to replace ltsp-build-client, possibly providing some example documentation or simple scripts for chroot builders (vmdebootstrap, grml-debootstrap), an ansible playbook, or possibly other methods. Ideally, we keep this a minimal feature replacement, and have most of the code run at boot-time rather than chroot-instantiation time.

In general, I'm inclined to default to an LTSP-PNP chrootless-style method, but there are a number of use-cases where a chroot will still be valuable.