roles/nginx: Add vim modeline to main.yml

Signed-off-by: Alan Orth <alan.orth@gmail.com>
roles/nginx: Add defaults for nginx role

Signed-off-by: Alan Orth <alan.orth@gmail.com>
roles/nginx: Use template to configure nginx vhosts

Signed-off-by: Alan Orth <alan.orth@gmail.com>