Move drush aliases to drupal role.

[thom8]

Proposed changes

To tidy up the Vagrantfile would be good to push the alias creation back to the drupal role and create project specific aliases in the root /drush directory rather than the users home dir.

https://github.com/beetboxvm/beetbox/blob/master/Vagrantfile#L200

[thom8]

linking geerlingguy/drupal-vm#1255

[thom8]

As there's a few of changes required for drush 9, it might be easier to remove this functionality.