Squashed 'vagrant/modules/postfix/' content from commit bd08c60

git-subtree-dir: vagrant/modules/postfix
git-subtree-split: bd08c60fc3ebf77e48cbb94e5249ea59d7570b92
Merge commit 'f1ed598bf4231fe62849ced1d4611545313e81c9' as 'vagrant/modules/postfix'
Merge branch 'master' of github.com:gchaix/webdev-vagrant
Add some dynamic port and IP stuff to the Vagrantfile