Make the Apache Document Root configurable

[whikloj]

I like the VM, but I would love to edit using my normal process/programs but see the changes in the VM instantaneously.
If the doc root was configurable, you could set it to your shared directory and be able to access the module code from outside the VM.

[ruebot]

👍

[lo5an]

We're likely to want this too, although our use case is slightly different. We run apps out of /srv across most of our systems, so we'll want our dev environment to match that.

Locally, I suspect that we'll put the Drupal install in the vagrant shared directory and remount it to something like /srv/islandora/drupal with the vagrant-bindfs plugin, but that's an extra hoop that most people might not be interested in jumping through.