Suggestion - add more instructions for the cdkv2 virtual box

PDF, Page 88

I suggest that you make it clear on the text that that the reader will need to download the following file:

https://access.redhat.com/downloads/content/293/ver=2.1/rhel---7/2.1.0/x86_64/product-software

and then run:

vagrant box add --name cdkv2 ~/VirtualMachines/rhel-cdk-kubernetes-7.2-25.x86_64.vagrant-virtualbox.box

For a newbie (like me) it was a little bit hard to realize that.

Thank you.