---maintenance option to bin/generate_apacheconf

[tmb]

This option should generate an auto-apache.conf that looks something like this:

 <VirtualHost *:80>
  ServerName <hostname>

  Options +FollowSymlinks
  RewriteEngine on
  RewriteCond %{REQUEST_FILENAME} !^/images/
  RewriteCond %{REQUEST_FILENAME} !^/style/
  RewriteCond %{REQUEST_FILENAME} !^/maintenance.html
  RewriteRule ^.*$ /maintenance.html [R=302,L]

  DocumentRoot "/opt/eprints3/archives/ARCHIVEID/html/en/"

 </VirtualHost>

With an additional VirtualHost? section for each alias:

 <VirtualHost *:80>
  ServerName <alias>
  Redirect / http://<hostname>
 </VirtualHost>

Also similar Rewrite statements for auto-secure.conf

This would make taking repositories hosted on a server down for maintenance a case of:

1. bin/generate_apacheconf --maintenance
2. restart apache
3. carry out maintenance
4. bin/generate_apacheconf
5. restart apache
6. normal service restored