role::deployment: port apache::vhost to apache::site

* Don't declare the default vhost just to ensure => absent it; it gets cleared
  by dint of Puppet managing sites-enabled recursively.
* Port the deployment Apache site to use apache::site instead of apache::vhost.
  The template I'm introducing for this site is simply a copy of the file the
  current Puppetization generated on tin, with some small fixes (leave
  ServerName undeclared; bind to *:80 rather than hard-code eth0's IP).
* There's a lot else to improve in deployment.pp but I'm here with a specific
  purpose. I don't want to be on the hook for cleaning up the rest of the role.

Change-Id: I12c6a042d3bb458b9d487356426f4d95b318f083
Merge "role::deployment: port apache::vhost to apache::site" into production