[TASK] Updates to match cookbook and application

The renderinghub just got a major update to the workflow, so this
updates the readme with accurate instructions. (They should work!)

Also, the cookbooks were slightly reorganized. This updates the
Berksfile and Vagrantfile to match those cookbook changes.

Related: TYPO3-cookbooks/site-builddocstypo3org#5
Resolves: #2