ref(user-data): "make discovery-url" copies from user-data.example

This also adds contrib/coreos/user-data to .gitignore, so that local
changes to this essential file do not cause "git status" to mark the
repo as dirty.
fix(Vagrantfile): require user-data when provisioning
Merge pull request #2118 from mboersma/fix-user-data

ref(user-data): "make discovery-url" copies from user-data.example
feat(store): add store-volume and store-metadata

These components enable the logger and controller to mount
a shared filesystem backed by CephFS.
fix(deisctl): adjust start order for logger/store
fix(deisctl): remove logspout from data plane
ref(logger): switch to ubuntu-debootstrap image