Bundle vagrant-vbguest plugin

Bundle v0.10.0 of the vagrant-vbguest Vagrant plugin to manage automatic
update of VirtualBox Guest Additions on the guest system.

Includes code from <https://github.com/dotless-de/vagrant-vbguest> and
<https://github.com/soveran/micromachine>.

Bug: 59712
Change-Id: Ib2efe79591c5c2f12833068fbe777831cb15f167