Add additional Vagrant providers (i.e. vagrant-aws)

[guruvan]

Vagrant supports a number of different providers including

vagrant-libvirt (kvm)
vagrant-aws

aws azure bhyve brightbox cloudstack
digitalocean ganeti google hp joyent
linode libvirt lxc openstack openstack-provider
openvz parallels proxmox rackspace scaleway
skytap softlayer vcenter vcloud vcloudair
veertu vmware-appcatalyst vmware-esxi vsphere vultr

No timeframe is set for adding additional providers. If you'd like one hastened please see BOUNTIES.md

vagrant-aws is expected to be first completed so that builder may take advantage of Very Large Instances to run builds significantly faster, with all disks in RAM