The `post-app-rename-setup` trigger redirected `sed` output to the new
app's VHOST file inside a loop over global vhosts, so each iteration
clobbered the previous one and only the last global subdomain was
rewritten. When no global vhost was set, the loop never ran and the
new app's VHOST file was never written, leaving the renamed app with
no domains.
Copy the old app's VHOST file once as a baseline, then apply `sed -i`
in place for each global vhost so substitutions accumulate. Guard
against a missing global VHOST file and skip blank lines.
The URLS file is no longer necessary as urls are now generated directly from the app VHOST file.
This also moves all the url generation logic to the domains plugin.
