CentOS basebox

[JGillam]

It seems like the right direction is to move from Amazon Linux to a CentOS basebox for the reference implementation on Vagrant builds. Amazon Linux will continue to be useful for AWS Workspace lab environments. CentOS is a close relative which means the bootstrapping steps and available packages should be similar.

Why? Using either the official or generic Vagrant boxes, we gain native Hyper-V provisioning, which addresses issue #151.

Options currently under consideration are:

• The official centos/7 box. This is provided by CentOS but on the downside it gets less frequent updates (last one was a couple years ago as of this post).
• The generic/centos7 box. This is unofficial, but hosted on Vagrant Cloud and frequently updated.

I like the idea of going with more frequent updates; however there is the risk that frequent are more likely to introduce instability at times, so that should be considered.